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1 



HANDBOOK 



CSE OK KI.KCTltlCIANS I.\ THE OPEliATION AND CARE 



ELEfTlllf^L MACHINERY AND APFAHATIS 



OF THE 



U. S. SEACOASr DEFENSES. 



PRKrAKKl) rXDKR TIIK DIRECTION OP THE LIEUTENANT GENERAL 
COMMANDING THE ARMY. 



SKCO>ri3 KDITIOlSr. 
OFFICE OF CHIEF OF STAFF. 



WASHINGTON : 

OOVKUNMKNT I'KINTIN(} OFFICE. 
I'M) J. 






WAR DEPARTMEXT, 

Document Xo 174. 

OFFirF, OF Chif-f of Staff. 



a 



PREFACE. 



The installation and management of the electric machmery in United States 
battleship.s merit the attention of electricians in forts. Its cliaracter and object 
in the two situations are similar, and the conditions of <lanipness. limited space 
changing personnel and reliability are equally severe. 

Every implement or portion of the fortification plant must be simple, certain 
in operation, effective, proved in the industries as standard in its class, and it 
should only be intrusted to the care and management of an efficient engineer. 
To l)e efficient he must have ambition, intelligence and the .skill gained by care- 
ful handling. The good order and working of his machinery at all times furni.sh 
thf only reliable testimonial regarding his fitness. 

Tlie preparation of the Handbook was suggested and aided liy the electricians 
of the class of 1900, Fort Monroe. It contains in full the latest instructions 
issued by designers and constructors. The portion relating to land and sea 
mines is intended for separate publication. The diagrams were drawn by First 
Sergt. Karl P. Runa. Notice of errors in this first edition will be thankfully 
received. — G. L. A. 

Boston, 1902. 

(3) 




United States Navy D. C. Set Constructed by General Electric Company. 5 



HANDBOOK VO]\ ELErTIJiriAXS. 



SPECIAL INSTRUCTIONS TO ELECTRICIANS. 



I. Your special duties are to secure the cleanliness and the best workinj? order 
of every part of the fortitication electrical eciuipnient f^iven to your care, wlietlier 
it he a Schukert OO-inch projector or a ^hiss insulator. 

'J. Upon taking charj^e of a plant, inspect it very carefully, and for your future 
protei-tion, in a letter for tile report everything found not in order, even to the 
tool marks on the machinery. 

H. For ten days, if i)racticable, the retiring engineer should operate, in your 
in-t'sence, all ai»paratus to be turned over and you, in turn, in his presence. 

•i. Take written notes in your notebook of the information he gives you. Secure 
all diagrams, i)lans and instructions relating to the machinery. 

."). Keep i)<)sted on boards, or in frames, in a lighted and frequented plac-e as 
soon as convenient : 

(1) Oil Engine Directions obtainable from The De la Vergne Companv, 
East 138th Street. N. Y. 

(2) The exact order of ()i)erating valves and switches in starting, running 
and stopping made out by yourself. 

(3) Instructions, Electric Storage Battery Company, Philadelphia, Pa. 

(4) Diagram of pipe connections. Engineer Office or yourself. 

(5) Wirijigs of dynamo and switch board. Engineer Office or contractor. 

(6) Blueprintofemplacements.showing wires, lamps, etc., Engineer Office. 

(7) Diagram of search-light connections, General Electric Comi)any or 
Engineer ( )ffice. 

(S) Diagram of each outside independent circuit under your charge. 

6. Take care of the ecjuipment in the following order of importance: 

( 1 ) Storage battery. (9) Firing, night apparatus. 

(2) Steam boiler. (10) Telephones. 

(3) Generating set, steam or oil. (11) Telegraphs. 

(4) Switchboard. (12) Night .signals. 

(5) Searclilight. (13) Anemometers. 
(G) External and internal wiring. (14) Lines. 

(7) Lami»s and outlets. (15) Electric bells. 

(8) Motors and hoists. 

7. Kee]i all machinery rooms clean, dry, ventilated and well lighted ; all sur- 
faces free from rust and dust, even if a banked tire or a kerosene burner is 
neces.sary. 

8. Do not delay work or repairs because exactly what you need is not at hand. 
Proceed with that which is obtainal)le and do tlie best thing possible so as to 
avoid making excuses. Even a good excuse is unfortunate. 

!•. Make timely re(p;isitions tor only the neces.sary and the best stores. Use 
best mineral oil only. 

10. If boiler, ingine, dyTiamo or any iron jiiece or tool is to ren)ain imtLsed, its 
polished surfaces will ])e tlioroughly cleaned in full light in a dry room on a dry 
day and covered with a thick, uniform coat of cosmic, witli 2.1 per cent of resin 
added if interval will be long. Every three months clean off, repolish and re- 
new. 

II. "Prevention " is the rule for machinery troubles, not "Cures." 

12. In ca.se of accident, "the other man " can not be pleaded by the electrician. 
The clearest evidence regarding liis capacity is furni.shed by a .single boiler 
fixture leaking, dirty water, incrusration or corrosion in boiler, an unsteady 



6 HANDBOOK FOR ELECTRICIANS. 

steam gauge, water glass, or fire, an unusual noise in engine, a hot bearing or 
coil, a scratched or sparking commutator, an oil engine's chronic cough or thick 
exhaust, density, voltage or gassing of storage cells not uniform, battery stand- 
ing at low voltage, burn-outs and tool marks on search light or other apparatus, 
dust, rust, or damp on any part, unsoldered joints or leaky circuits, and by other 
things. 

13. A neat and well-fitting imiform will invariably be worn outside of the 
emplacements. 

14. Always charge a storage battery at its given normal rate to full charge 
(density, 1.200; voltage, 2.5 per cell); do not discharge above the normal rate 
except in emergency, and never below density of 1.175 and voltage of 1.8 per 
cell. 

15. Keep density, voltage and gassing of all cells uniform. To cover plates 
I inch, water (or solution, 1.400, rarely) is added at the top directly after charg- 
ing begins. If little used, the battery is partially discharged and regularly 
charged once each week. 

16. Blow off boiler in starting at 10 pounds from water high, one or two 
gauges; oftener if necessary. Maintain uniform fire, water level, and pressure. 
Frequently inspect fire tubes for dirt, and boiler interior for deposit and corrosion. 

17. Handle all machinery and apparatus with great care. Let their loads be 
increased and decreased uniformly and slowly. Guard against sudden rise of 
temperatures. Never hesitate to allow a machine to take its full load imder 
these conditions, but not to exceed it. 

18. An engine is always started as slowly as possible. A good engineer turns 
valves and switches deliberately while watching the effect; his order of starting 
and stopping is always the same. 

19. Keep exposed conduit, cut-oiit, switch, junction and lamp boxes cleaned 
and painted, and all openings tightly sealed, so that the whole system is essen- 
tially air-tight. 

20. For more complete information, electricians are referred to Crocker's (two 
volumes) Electric Lighting, Sheldon's Dynamo Electric Machinery, Genei-al Elec- 
tric Company's Bulletins and Instructions, Westinghouse Company's Bulletins, 
Dawson's Electric Traction, Treadwell's Storage Battery, Goldingham's Oil 
Engines, Miller's Telephony, Maver's Telegraphy, Cushing's Wiring, Strom- 
berg's Steam Engine, Hawkins' Catechisms of Electricity and Steam Engine. 

21. The efficiency of all your machinery was long ago proved. The opinions, 
sometimes heard, that search lights, for instance, can not be controlled from a 
distance, that storage batteries are inefficient, that telephones near guns are 
inoperative, that oil engines and submarine mines are unreliable, result from 
the kind of knowledge which is dangerous. 

22. In more than nineteen cases out of twenty in which a standard machine or 
apparatus, properly installed, fails, the fault rests with the attendant. 

23. Remember that if there is any portion or piece of the fortification electrical 
equipment under your charge not in perfect working order, or not clean, and not 
reported as irreparable, and if you being for duty, are working less than ten 
hours daily on week days, you will be held blamable. 



I.— HANDLING AND CARE OF STEAM FIRE-TUBE BOILERS. 



(A) IIAISIN(; STEAM. 

1. To start the fire in a small fnniaee, clean the j^-ate of clinkers and the ^it 
of ashes. See that grate works freely. Cover it evenly with shavin,i,'s and 
wood and lifjfht the fire. When the ni)j)er stratiiniof hard wood is blazini; well, 
throw on a nnifonn 2-incli layer of soft coal, closin;.^ furnace and openint,' tlu'pit 
doors. When the coal is red, add a second similar layer. A tliird feeding shonld 
leave a greater depth of coal around the sides than in the center. 

2. If the furnace is large, cover the grate all over with a 2-inch layer of hard 
coal, except a space in front for wood and shavings. Cover the coal at the back 
witli a little heavy wood and light the fire. Add coal to the npper hard Avood 
when aglow, as above, and so continue. 

13. Regulate coal and draft for at least one hour's rise to full pressure in a small 
warm boiler, two hours for a small cold water boiler an<l fi\-e or six hours for a 
large cold boiler. 



Horizontal Boiler for a Stationary En^ne. 



» STCAM N07ZLE 




t?" \-^-:li ' ' > ;' W ' g ^ 






( ,97,, 

2. Horizontal Return l-ire-Tube Steam Boiler. 



4. After lighting the fire see that : 

(a) Gauge glass agrees with gauge cocks and is not choked. 

(b) Water stands to ni)pt'r gauge at lea.st. 

(c) Safety valve is in working order by rai.sing it once or twice. 

(d) Steam feed, throttle, and blow-off cocks tare closed. 

(e) Pum]) is oiled. 

(/) Upper gauge is temporarily open to ecpialize the ])ressure within. 

5. At 10 to 1.") ])ounds i)ressure blow off to second gauge to drive out mud and 
create circulation for even teini)eratnre. 

(IJ) FIRIKG. 

1. Before opening the furnace door have jdenty of coal at hand — no piece 
larger than the fist. Spread the coal by throwing to the rear first and so on to 
the front in a thin uniform layer. !Most firemen heap on too much fresh coal. 

2. The thickness of coal fire is from 5 to S inches. If the nece.ssary tliickness 
makes too hot a fire, reduce the grate area by i)utting in fire brick, 8 inches high, 
around the sides of the furnace. 

3. If the fire bums tinequally, fill the vacant spots. Allow no air holes in the 
bed of fuel. 

4. The cdeaning tools are: The hoe for pulling or pushing the fire over the 
bars, .slice liar for breaking n\) the fire, cliiiker liook and tlie T bar for raking 
lengthwise of the bars beneatli tlie fire to cause the ashes to fall through, and 
scoop shovel. 

5. Clean or rake the fire as rarely and as quic-kly as possible, but always when 
clinker and ash are closing the grate, usually two or three times a day if coal is 

^7) 



8 HANDBOOK FOR ELECTRICIANS. 

hard. Dark spots, heavy smoke, and blire flame give warning. But leave the fire 
alone so long as it is at nniform glow and its light shows in the ash pit beneath. 

6. To clean a fire, have plenty of water in the boiler, open damper and one fur- 
nace door, pack half of the fire to one side, raking out the dead clinkers and ash; 
then move the whole fire to the exposed grate and clean the other half; finally 
spread the fire evenly and throw on fresh dry coal. Cleaning reduces the depth 
of fire and lowers the boiler pressure. Shaking the grate is the best way to clean 
when it can be done. 

7. The most effective and economical fire is moderately thick, steady, uniform 
and regulated, as far as possible, by the chimney damper. Enough air should be 
admitted above the fire through the door air holes to consume the rising gases 
and thereby increase the heat. With a steady fire the combustion is more per- 
fect and there are less clinkers, less cleaning and less cold air. 

8. The construction of a damper should not admit its closing the chimney 
entirely, as gases may otherwise collect in the flue and cause explosion. 

9. To bank a fire, have three gauges of water. Allow fire to get low, clean 
and push it to the rear in a compact pile and cover it thickly with small coal or 
wet ashes. Leave clinker and ash on the front of grate. Leave fire doors 
open and close the pit doors tightly and the chimney damper partially. If the 
fire is found too cold the next morning less grate should be uncovered and the 
pile of fire be less compact. Banking the fire preserves the boiler by keeping its 
temperature more nearly even, saves time in starting, but is dangerous if not 
properly done. 

10. To start a banked fire, clean out ashes and clinker or shake the grate, 
spread the fire evenly, feed a little wood for draft and add coal gradually 

1 1. Ashes left high in the ash pit may cause warping or burning out of grates. 

12. When fuel and water are irregularly fed, or pressure is always changing, 
or the safety valve is now and then popi^ing, or dampers and doors are being 
frequently opened and closed, or if there is a leaking of water, steam or oil, or 
room is dirty, the boiler's tender is outside of his sphere of usefulness. 

13. Give the last two or three miniates in a boiler room to its inspection to 
make sure that everything will be left in order. Then close and lock all doors 
and windows. 

(C) CARE AHfJy MAIS^AGEMENT OF STEAM BOILERS. 

1. The steam boiler is the most important element of an electric plant. 

2. An indifferent or intemperate fireman and a cheap boiler are alike dangerous. 

3. The first thing on taking charge of a boiler is to inspect its safety-fitting 
and feeding apparatus. 

4. Let the ear aid the eye in detecting troubles. 

5. Never exceed the working pressure given by the builder or inspector. 

6. Never open nor close a throttle, a blow-off or other steam outlet suddenly, 
nor leave it before it is closed. 

7. Repair a leak or a damage in boiler or fitting as soon as possible. See that 
fiirnace, combustion chamber and smoke flue are tight. 

8. Mi;ch smoke from the chimney shows that combustion is not perfect. All 
air must go through the grate bars or the little smoke burners. 

9. The boiler room should be day lighted, well A'entilated, spacious and dry. 
Never leave it while boiler is under steam. 

10. Dry steam only is wanted. If a small jet from the upper gauge cock, close to 
the orifice, is transparent or even has a grayish-white color, the excess of moist- 
ure is less than 1 per cent. If the jet is strongly white, the excess is 2 per cent or 
more. Steam containing less than 3 per cent excess of moisture is fairly "dry." 

11. Empty a boiler working daily once a fortnight. If water is muddy blow 
out 6 inches daily and use the surface blow-out more frec^uently. To avoid 
serious results exanaine blow-out and check valves whenever the boiler is filled. 

12. Procure the manufacturers' directions of boiler and its fixtures. 

13. Blisters and cracks may occur in the best boiler plate. Then put the boiler 
out of service and repair. 

14. In case of low water, immediately open furnace doors and chimney damper, 
close pit docjrs tight and qiiickly cover the whole fire with ashes, soil or coal 
(wet if possible). Leave all steam outlets as they are. Do not draw fires until 
the i)ressure has dropped, nor turn on feed water, nor start nor stop engine, nor 
lift safety valve until the fires are out and the boiler is cooling. If water has 
only just disappeared there is no immediate positive danger. If the water gets 
too high, carefully open blow-off and let out gradually a gauge of water. 

15. Foaming or priming is due to forcing the boiler or to small steam space 
or to other bad design or to dirty or high water or to opening the throttle 



CARE OF BOILERS. 



9 



1 . Every steam boiler requires th 
sill]), correct settins:. economy of 



suddenly. There is rumbling in tlie l)i)iler. the glass gauge jumps up and down 
and there is danger of water being carried over witli the steam and of bursting the 
cylinder. Partially closing the tlirottle may stop it. If high or dirty water is 
the cause, blow off and punij). If the foaming is violent, check the draft and 
fires. The true water level can only be seen by closing throttle or supply-pipe 
valve long enough to observe. 

16. If a boiler stands unused for'a few days, fill it to the top; adding a Httle 
common wa.shing soda is excellent. If it remains idle for some time, emjity it 
and dry thoroughly with live coals inside the man or mud hole, allowing draft 
through the safety valve. Sometimes (juicklime is used. Disc-onnect the feed 
steam andldow-off' and finally seal the lioiler air-tight by closing all oi)enings and 
coating the joints with cosmic. Finally coat the boiler and fittings with 
linseed oil. 

17. A boiler must be cool when filled. Never allow water from leaky joints or 
other source to come in contact with the exterior of the boiler. Feed Avater should 
enter in the direction of the boiler's circulation, and not near a heated surface. 

18. A good engineer maintains a steady fire burning as slowly as the recpiired 
pressure will perjiiit. uniform height of water at the middle gauge and a uniform 
pressure. The safety valve, gauge ^lass, injector, valves, etc., are always in 
the best working order and constantly watched. All joints, connections and 
packing are tight. He knows the extent of scale, corrosion, and soot. All oH 
his machinery and rooms are kept in order. 

(D) THE STEAM IJOIEEl? AXl) ITS FITTIXOS (Vlii. 3). 

ebest materi.al, the highest grade of workman- 
maintenance, capacities for steam, water and 
fire, heating surface to maintain the max- 
imum pressure, free circulatioia of water, all 
parts accessible for cleaning, and repairs, 
comidete combustion of ftiel, joints and 
weak parts not expo.sed to fire, minimum 
repairs, constant vigilance, and care. 

2. The piping is water-tight, smooth inside, 
direct, and so arranged as to take up exjian- 
sion and not to collect water. All fianges 
and fittings are carefully put together. Rub- 
ber gaskets are essential between flanges to 
prevent leakage from jiressures under 100 
pounds; soft copper for higher ])ressures. 

(o ) Pipes conveying live steam are covered 
AAnth asbe.stos or other noncoiiducting and 
noncombustible material, by whiidl the loss 
of heat is often reduced three-fourths. 

(b) All valves of brass or bronze are globe 
or gate, operating automatically or by means 
( >f an ( )utside handle. Leakage is often caused 
l)y dirt or sticks in the water. Never close a 
valve or a cock so loosely as to leak nor so 
closely as to bind. The last lialf turn in clos- 
ing is made very slowly, if, like the throttle, 
it checks a heavy pressure. Valves lift about 
(me-fourth their diameter. 

8. The .safety valve is raised daily by hand 
to guard against sticking or tampering. 

4. (Fig. 4.) The main valve T'isheld downi 
on the two circular seats J/ and A' against the 
steam i)ressure by the spring S acting on the 
rod T. The outer seat A' is formed on the 
body .1 of the valve, while the inner and 
smaller seat .1/ is formed on the upper edge 
of a cylindrical chamber B which is con- 
nected to the body A by arms containing the 
passages t' C. The hollow chamber B forms 
aguidefor the valve 1'. Ordinarily the steam 
exerts a ])re.ssure ( >n the amnilar space l)et ween 
J/ and .V; when the valve rises a little the 
steam ru.shes over the seat iV into the air, and 
over the seat -1/ into the chamber B. whence 




3. Upright Boiler. 

1. K, smokestnck ; II. wri^lit safety vnlve ; 
O. ffeii l>ii>o; .S. .<tciim spiuc , /', pri'S-iurc 
jriiiif : (' '■ '', KiiiiK'' cocks ; I', wiittT liiu' ; I t, 
fiir nilii's: .V, fceti pipt- with stup viilvc; 
M MM. tmn.l holi-s ; o .i. stay l.olta ; F. fire 
I't'X ; E. gnito ; U, ash pit ; k, riug ; 



10 



HANDBOOK FOR ELECTRICIANS. 




it escapes through the channels C, C. The channels are, however, not large enough 
to allow the steam to escape from the chamber as fast as it enters, and hence the 
pressure in the chamber rises and acts on the area inside the seat M. This addi- 
tional pressure throws the valve wide open and 
quickly relieves the pressure in the boiler. 

(o; Steam escaping from a safety valve is a sig- 
nal of safety. It is set to open at 5 pounds above 
the working pressure. Changing, overloading or 
neglect is dangerous. About 1 square inch of valve 
opening is necessary for 3 square feet of grate sur- 
face. 

(6) To set a weight safety valve : Steam pressure 
in lbs. X valve area in sq. ins. X dist. from fulcrum 
to center of valve = lbs. required to raise lever X 
length of lever. 

5. The pressure gauge is a brass circular tube of 
oval cross section having the open end connected 
with the boiler space by a pipe so bent as to retain 
water in the tube. The steam pressure on the 
water tends to make the oval section circular and 
therefore to straighten the hoop, whose free and 
closed end in moving turns a pointer by means of 
gearing. The pressure shown is that above atmos- 
phere. 

It must be accurate over the whole scale, should 
stand at when there is no pressure and agree 
with the safety valve at blow-off. If not, compare 
it at once with another gaixge and correct. The 
length of the invisible jet from the upper gauge 
cock is a rough check. 

6. The gauge glass is the boiler fixture most 
closely watched. A majority of accidents are 
attributed to a choked water gauge which is never 
to be relied upon, especially when the boiler is 
foaming, unless verified by the three gauge cocks. 
Before firing and occasionally during the run, blow 

out the glass twice to see that water returns to the same level and both pas- 
sages are clear. 

Cold drops of water or currents of air or scratches in cleaning are liable to 
fracture the glass. Then close lower and upper stopcocks, replace from stock 
always on hand by a new glass and soft rubber gaskets, taking care that the 
glass does not touch metal. 

7. The three gauge cocks are tried many times every day as a check upon the 
indications of the glass and pressure gauge and are more reliable. The upper 
cock should show dry steam ; the middle one, steam and water ; the lower, water 
only. 

8. The scum cock, for blowing out dirt from the surface of the water, is opened 
and closed alternately and cjuickly to prevent clogging. Continue so long as 
scum appears. 

9. The blow-off cock of gun metal with metallic packing is opened at least once 
a day to guard against sticking. To insure against the blow-off being left open, 
the handle is a removable spanner or key which can only be put on or taken off 
when the cock is closed. 

Blowing down at about 10 pounds pressure while raising steam drives out 
impurities on the bottom and equalizes the temperature throughout the boiler. 
If the pressure is high, open deliberately and keep the hand on the spanner 
while watching the glass. Make sure to close the cock. If water falls unac- 
countably in glass, look to the blow-off. 

10. The feed pump (fig. 5) is an engine to be cared for and handled much 
like the main engine. It must be simple, double-acting, quiet, without leaks, 
jjositive under varying jiressure, and have a suitable location, no dead center, a 
full supply of water, both a check and a stop valve in the delivery and a check 
valve and strainer at the suction extremity. 

{a) The iiump end is in good order if the pet cock, when opened, shows full 
stream at forcing and weak at suction. Streams on both suction and forcing 
strokes show that the pump valves are not closing. If there is no stream, look 
for air leakage in the suction or no water supply. If the receiving valve does 
not close, the pet cock shows hydrant pressure. 



4. Pop Safety Valve. 



CARE OF BOILERS. 



11 



(b) If pninp goes slow, tlie packing may be too tight or suction may l)e dosed 
or steam lias tallen. The packing is tight enougli if on closing the delivery 
valve tlie plunger makes a stroke up and down and then stops. 

(r) If till- pump gets hot, water may Ite backing into it past th.- cli.-ck valve 
ironi the Ixiilcr. 

('/) If an accident hapi)ens to a pump and there is no injector, stop the engine 
close boil.-r valves, draw the fire, raise tlie tlue caps, and close the damper 

in If the .suction i)ipe leaks, wrap sheet rubber over the opening and bind it 
tight witii string (n- cijjiper wire as a temporary repair. 

(/) A .steam boiler recjuires both a pump and' an injector, each capable of sup- 
lilymg 1 cubic foot of water per horsepower per hour. 




END VIEW OF STEAM CYLINDERS 



PISTON Pattern WATER end 



5. The Worthinuton Pump. 



Steniii rvliiiili-r (X... 1 an. I 

No. 2). 
Stfuiii-ivliii.liT luiiil. 
Sliilc viilv.-. 
Viilv(-ro<l nut. 
Viiivi- roil. 
Vnlve-icKl v'lnml. 
Viilvi-r.Ml li.-itil. 
Stfiuii clu-.st. 
Stciiiii-clictit nivcr. 
Stt'iiiii |ii|if. 
ri>t.iii riiiii. 

ri>l..h fnll,,«,T. 
risl..||.f.,|l,,w,.| hcilts. 
VixUm I..mI>. 
PiHtoii imiKiif. 

I*i.s|4i||.(ii||);i||. >|vnil)I. 

I'ifitiiti.t«)ii>;iir Imuki't. 
Pi^<tl>ll-lc»l sliill ritf l.ox. 
I'istdii-rnil.sdilhiiK-lHi.vfcliind. 
Stciilii-rvljiicli'i' fnut. 
Exlmuiit tIaiiKf. 



■s.i. 


I'islon 111(1. 


•I-'. 




24. 


Aiilvp-i-dd licii.l pill. 


43. 


Hinder. 


•A). 


■Niilvc-rodliiikd.iiiKorstii.it). 


44. 


I'liniRer luili. 


2ba 


LdiiK lever. 


4.5. 


Water-cylinder linnil-li(ilc 


27(1 


Slloit lever. 




plate. 


2Tfc 


Koik eii.l. 


46. 


Force clininlier. 


2S. 


K(.(k-sliaft kcv. 


47. 


Koive-clianilier liaud-liole 


2'.l. 


I pper ruck sliiift. 




]>late. 


311. 


Lower rock »buft. 


4X. 


Valve Kiiard. 


31. 


Cniiik pin. 


4!l. 


Valve Kpriii)^. 


32. 


SlKWl. 


SI. 


Valve. 


33. 


Spool poiiitioti pin. 


52. 


Valve Beat. 


M. 


S|MK.l key. 


63. 


Delivery tee. 


3.1. 


('nidle. 


54. 


.\ir clianilier. 


3t>. 


CroKK Htiind. 


5.i. 


Suction tlanKL>. 


3V. 


Hlow cook. 


57. 


riidoii nut. 


•.m. 


\\utei' cylinder. 


6f<. 


i*liini;er nut. 


3!t. 


Wiiter-cvlinderlieiid. 


fil. 


Wal(i-(\ Under fo(,t. 


4(1. 


I'liinijcer. 


f>:i.i 


.Solid water pidloti rin«. 


41. 


I'lniiRer rinK or cylinder 


K5. 


Packed water pinton liodv. 




liuiuK. 


•;•;. 


Packed water piutuii followe 



12 



HANDBOOK FOR ELECTRICIANS. 




11. The injector lifts, heats, and forces the water into the boiler but it is not 
so easily regulated to a small continuous flow as the pump. 

(o) It has four nozzles: The steam nozzle 4, through which a jet of steam 
from the top of the boiler first passes ; the combining nozzle C at whose extrem- 
ity the steam and the water from the supply unite ; the condensing nozzle D 

in which the steam's 
condensation is com- 
pleted, and the deliv- 
ery nozzle, seen just 
above 3, to the bot- 
tom of the boiler. 

{h) There are four 
openings — steam, wa- 
ter, overflow and de- 
livery. 

(c) The Hancock 
injector (fig. 6) with 
40 pounds dry steam 
\x\\\ lift water below 
100 F. up 25 feet and 
force it hot into the 
boiler. It has globe 
valves at 4, 5 and 3 
and a check and globe 
valve to boiler not 
shown. 

(I) To lift the water 
and to inject it, open 
valves 3, 1, 5 and 4 in 
order. Steam rushing 
through 4, C and D 
t o w a r d overflow 3 
drives out the air. 
Water rises in 5 to C 
and the steam jet is condensed by it at D. The resulting hot water jet has less 
cross section than the steam, but equal energy at the overflow. When the flow 
of water here appears steady, close 1 to turn the stream through D, open 2 one- 
half turn and close 3 to direct the flow into the boiler. The ear will recognize 
proper action. The jet into the boiler can be somewhat reduced by partly 
closing the water supply 5. 

(II) To inject simi)ly (the supply being above the injector) leave 1 always 
closed and open 3 and 5. When cold water appears at overflow, open 2 and 4 
and close 3. 

(III) Metropolitan, Rue and Korting are other good injectors similar in action. 

(iv) Failure to act is due to improper handling, leakage of air, water insuffi- 
cient or too hot, jn-essure too low or too high, or to obstructions in the tubes. If 
the stream breaks unexpectedly, look first to water and steam supply for the 
cause of the trouble. 

(v) If hard scale forms on the nozzles, scrape it oif or soak the injector in a 
one-tenth solution of nauriatic acid or boil it in a mixture of vinegar and salt. 

(vi) All pipes, valves and fittings of pump or in- 
jector must be air-tighf and agree in size with pump 
or injector openings. The suction pipe is larger if long. 
Keep the fine wire strainer at its extremity clean. 
Injector and pump require each its own check valve and 
a stop valve in common in the delivery. Neither will 
lift hot water. There ought to be a water heater 
between the pump and boiler if the supply is cold. Use 
injector if the pump can only inject cold water. 

12. A fusible plug (fig. 7) screwed into the crown sheet 
of a furnace, may not act unless examined and scraped 
clean on both furnace and fire sides whenever the boiler 
is cleaned. R is the fusible metal in the upper part of 
the plug P, so that when it melts from low water there 
is still water covering the crown sheet Q. 

13. Several manholes are placed in large boilers, and hand-holes in small, for 
purposes of inspection and cleaning. Gaskets are liable to get hard or to become 
torn so that at least one extra set should be kept on hand. 

14. The grate clogged with clinkers or ash stops the draft. 




7. Fusible Plug. 



CARE OF BOILERS. 



13 



(E) TPIE FEED AV^ATER. 

The feed water ought to be pure and liot. Rain water is usually satisfactory ; 
well water is often good, souietinies very bad for the boiler. When the souree 
is xuitried or the boiler is new, the man or hand holes are freciuently opened to 
see if incrustation, corrosion or both have oc-curred. These maladies are the 
two greatest evils that operate against the life and safety of steam boilers and, 
unless prevented, will burn, granulate or distort the jdates and tubes or cause 
pitting, grooving or wasting which results in exjdosions. 

1. Incrustation. 

(o) Well water generally contains salts of lime, magnesia, silica and ahimina. 
When tlie water is heated und(>r pressure they are liable to separate from the 
wati'r forming at fir.st a sof t deposit. Heat further bakes V.w sediment ujion 
the boiler's interior into a nonconducting stone-like or glass scale which sepa- 
rates the water from the i)lates and leads to dangerous overheating; -j'^r-inch 
scale makes 15 per cent more heat necessary. 

(/>) To maintain !)0 pounds pressure, water miist be heated to 320' F., and a 
clean boiler fire surface to :V25 F. If ^-inch scale intervenes, the fire surface 
must be raiseil to 700' F. Al)ove 600^ F. iron becomes gi-aniilar and is liable to 
bulge or crack inuler i)ressure. 

((•) Incrustation can be i)revented (i) by an expensive purifier which heats 
the water before entering the boiler until the .salts are i)recipitated ; (il) often by 
chemicals of pure (piality such, for I'xample, as caustic soda for lime carbonate 
deposit, or carbonate of soda for lime sulphate deposit, or good kerosene, etc., 
with more frequent blow-offs; (in) sometimes by frequent use of surface and 
bott<mi blow-offs alone. 

The chenn-jals (ii) simply make the hard deposit soft. They should be uni- 
formly added in weak solutions to the boiler bj' way of the i)ump, gently at first, 
and tht; effect carefully watched by an experienced X'crson. Excess muy cause 
boiler leakage. Let the first trial be at the rate of I jxmnd .salt per horsepower 
per month, or one cpiart daily of kero.sene ])er 100-li(U'sei)ower. Avoid all nos- 
trums. Where tlie supply is poor, a good remedy lies in a large cistern and a 
wide roof, from whit-li the first water of every rain is not collected. 

((/) When tlie hard scale has been once deposited, the most certain remedy is 
to chip or pull it off by hand. 

(e) Some waters having magnesia, etc., throw dowTi a fine floury deposit which 
^^•ith little grease from the exhaust, and under iiressure, often strains seams and 
rivets, causes leaks and bulges furnace plates. Oil filters and spare use of oil 
are remedies. 

2. Corrosion. 

{(() Corro.sion is internal or external. Few boilers after .some service are 
wholly exemjit from intting, grooving or wasting away in irregular and ill-defined 
patches. Internal corrosion (fig. 8) is the most destructive of all boiler diseases 
and .serious enough to demand aremedy 
at once and subsequent careful watch- 
ing. Stay bolts and rivet heads are 
sometimes attacked. 

(b) It may be due to acid from vege- 
table matter in feed water, or decom- 
position of acid salts in the scale, or 
other impurity in hot water under high 
pressure, or to galvanic action. Tlie 
ill effects can generally be reduced by 
pure soda ash, in .solution, uniformly 
added by the pump. If galvanic action 
is suspected, fa.sten blocks of zinc into 
good metallic contact with boiler parts 
and near the i)atches. Change of water 
may cure. Or, let a chemist discover 
and apjily a neutralizing agent. 

(c) To ])revent external corrosion. 
allow no water to come in contact with 8. Corrosion Next a Lap. 
the boiler's outside, or dampness from 

leaking to remain in the seatings and coverings. Finally coat A\ith lin.seed oil. 
((/) A sensitive hydrimieter. finely graduated above unitj' over a short range, 
will aid in detecting the waters which cause scale or internal corrosion. 




14 



HANDBOOK FOR ELECTRICIANS. 



(F) CI.EANING THE BOILER. 

1. While cleaning, watch for faults. 

2. The heating siirface, first of all, should be kept clean on both sides. Never 
allow scale or soot to exceed y\ inch in thickness. A chisel may be used for 
scale ; a scraper, chain or wire brush, and not steam, for flues. 

3. The water in the boiler is changed every two or three weeks. 

4. Empty and thoroughly clean once in five hundred working hours, of tener 
if tiie boiler is new or the water is bad, or the work has been intermittent. The 
interior, after it has cooled, is washed down with a hose and dried, all scale is 
removed and the boiler again washed. A small chain is sometimes dragged 
around the tubes to clean them. Before closing the manholes remove crust and 
tools that they may not choke the blow-off. 

(G) THE INSPECTION OF A BOII.EK. 

1. By a legalized inspector, once a year, extends to every part and fixture of the 
boiler, first empty and then under steam, after the defective parts have been 
replaced. 

2. Boiler, fliies and mud drum are first cleaned and dried in order to be seen. 

3. The inspector ascertains the soundness and thickness of the plates by the sound 
and rebound of a very light hammer. The hammer test is iisually sufficient. 
He notes tlie location and amount of incrustation and corrosion, and searches for 
blisters, cracks, loose rivets, broken or corroded stays, fractured joints, etc. All 
seams, head, and tube ends are examined carefully. A doubtful spot is exam- 
ined with the aid of a magnifying glass. Sometimes a small hole is drilled 
through and, after inspection, plugged. 

4. A loose rivet is replaced. A stay, brace, or fastening found defective, or a 
tiibe cracked is taken out and a new one is put in. A blister or a bulge is cut 
out and a patch is riveted inside if possible. 

5. The hydraulic test is made when the boiler is new or extensively repaired 
or can not be thoroughly examined inside and ovit. Fill the boiler with water, 
close all oiitlets and use the force pump very slowly and evenly until the pres- 
sure is one and one-half times the working pressure. Or a gentle fire may be 
started under the filled boiler to get the desired pressure, but the temperature of 
the water should not exceed 212^. There is no danger of explosion if boiler is filled. 

Watch the gauge closely for any drop in pressure due to the boiler's yielding. 
By fixing points of sticks or wire close to the outer surface of furnace .sheets, 
shell and ends, any deformation due to pressure may be detected. Any leakage 
in seams, rivets or joints is calked before continuing the test. 

6. Under steam, the pressure gauge is compared with a standard along its entire 
scale; the safety valve is raised, operated, and, if necessary, reset. Look for 
leakage in cocks, valves, joints, and all fixtures, and for any faulty action in 
gauge glass, pump and injector. 

7. The inspections of a boiler begin at its manufactory and continue so long as 
it is in use. 

(H) EXPIiOSIONS. 

About 250 steam-boiler explosions occur annually in the United States, mainly 
due to preventable causes. Vigilance and execution of the foregoing rules will 
prevent them. When the first symptom of a disorder appears, apply the remedy. 

In 1893, a single American insurance company examined 163,000 boilers, in- 
spected 67,000, tested hydrostatically 8,000 and found 600 unsafe. In all, 123,000 
defects were discovered, of which 12,000 were dangerous, as classified below: 



Nature of defects. 



Deposit of sediment 

Incrustation and scale 

Internal grooving 

Internal corrosion 

External corrosion 

Defective braces and stays 

Settings defective 

Furnaces out of shape 

Fractured plates 

Burned plates 

Blistered plates 

Defective rivets 

Defective heads 



Whole 
No. 



Dan- 
gerous. 



548 
865 
148 
397 
536 
485 
352 
254 
640 
325 
164 
,569 
350 



Nature of defects. 



Leakage around tubes 

Leakage at seams 

Water gauges defective 

Blow-outs defective 

Deficiency of water 

Safety valves overloaded 

Safety valves defective 

Pressure gauges defective 

Boilers without pressure gauges 

Unclassified defects 

Total 



Whole 

No. 



21,211 

5,424 

3, 670 

1,620 

204 

723 

942 

5,953 

115 

755 



122, 893 



Dan- 
gerous. 



2,909 
482 
660 
425 
107 
203 
300 
552 
115 
4 



12, 390 



CARE OF BOILERS. 15 

The various causes are : 

1. Excessive pressure, due to carelessness of the engineer who ought to have 
been intelligent, well paid and legalized; and to defective pressure gauge, safety 
valve and ol)servation of water gaugt — all three combined. The working i)res- 
siire sliould not exceed two-thirds of the water test or one-fifth the safe theoreti- 
cal pressure. 

2. ( )vfrlieating of plates due to low water or scale. While boiler is under 
steam the water line sliould always stand at the middle gauge, and the water 
glass .should be cleaned and watched. 

To stop scale, inspect and clean boiler regularly, l)low off sufficiently often, 
use the scum cock, seek the i)roper solvent and change the water, if necessary. 

8. Corrosion in patches and holes. After some explosions, plates are found 
wasted in places to tlu' thickness of paper. Vertical bf)ilers are more liable to 
ex])lo(le from corrosion at the ends of tubes. Keep boiler full of water if it lies 
idle a few days. 

4. Bad construction in material, design, or workmanshij). There is no remedy. 
Tlic ]irfVfntioii lies in i)urcliasing boilers from a standard maker. There is only 
one grade of boiler to be selected, i. e., the best. 



II.— THE STEAM ENGINE. 



The type generally used in isolated plants is a simple, donble-acting, single- 
slide or piston valve, automatic cut-off, high-speed, high-pressure, hori/contal or 
vertical, direct-connected, steam engine. All types involve similar principles 
and require the same kind of care. 

(A) ITS OPERATIOIV. 

STARTING. 

I. Drain water out of steam feed pipe and close the drain. 
3. Make sure that every part of the plant is in order. 

3. See that both cylinder drains are open. 

4. If the engine is not too large, turn it over by hand to see if it runs smoothly 
without play and leave the crank at 45 degrees, leaning toward and moving from 
the cylinder. 

5. Open the throttle a small fraction of a turn to drive out water and to warm 
the cylinder while oiling. 

6. In a regular order fill the oil cups and oil all bearings, and make sure that 
oil is not choked by giimming anywhere. 

7. The cylinder must be warmed some time to allow fi*ee motion of the valve 
and piston. 

8. Widen throttle slightly to start engine as slowly as possible during the first 
dozen turns. 

9. Bring engine to full speed very gradually, standing ready to close instantlj'- 
if a blow is heard. 

10. Then turn throttle wide open. 

II. Close the drain. 

12. Adjust the oil cup and lubricator feeds, two to five drops per minute 

RUNNING. 

1. The engine should run without noise. Lost motion is taken up gradually 
as soon as it is detected. 
3. The ear may aid the eye in detecting troubles. 

3. Watch for heating especially in crank, crosshead, cylinder, stuffing boxes, 
main bearings and eccentric. When found, ease away on nut or key when 
possible and increase oil to which melted tallow may be added. Correct the 
fault at the first stop. 

4. Uneven speed indicates sticking of the valve or governor parts or loose 
connections in the valve motion. 

5. See that oil cups feed x)roperly and that no bearing surface is dry. Guard 
against the use of too much oil. 

6. A click in the cylinder from water should be quickly recognized. Open 
both drains until it stops. 

7. An" engine running requires constant vigilance and labor on the part of its 
attendant. There is no place for company or a chair in an engine room. 



1. Slow down engine gradually, especially if pressure is high, and be deliber- 
ate in last half turn of throttle. Leave the crank on outer dead center. 
3. Close all oil cui)s. 
3. Open drains and loosen belt. 

(16) 



THE stea:\i kn(;ink. 17 

4. Feel crank, crosshead and other parts for heat. 
~). Clean tlie engine thoroughly while warm. 

6. Clo.se the room tight, locking doors and \vind()ws, that engine may cool 
slowly. 

(IJ) GENKIIAI. < AKi: AXl) ^[ANAGEMKXT. 

1. Never attempt to adjust a key or part without first marking its original 
po.sition with a pt-ncil or a metal i)oint. 

2. After making an adju.stinent run at first slowly on no load and on light 
loads. Experimental changes should never he allowed. 

8. If the engine is unexpectedly stopped and the steam pressure is high, throw 
fre.sh coal on the tire, close damper to grate, open the furnace door, and start' 
the pump. 

4. Keep steam at uniform pressure while riinning. 

5. If engine is new or ju.st overhauled, run it slowly \\nthout load ami with 
light loads for hours to let it wear to its hearings. 

(>. A cleaidy kept engine in good order attests its engineer's caijalnlities. All 
hearing parts are kojjt free, smooth, oiled and without lo.st motion. 

7. The new man gains all the information jtossihle from the retiring engineer 
and should jiosscss the manufacturer's directions. 

■''<. No loose garment should he worn ai'ound an engine in motion. 

!». Do not tinker with the engine. If it is necessary to repair some i)art, do it 
thoroughly and look f)ver all other ])arts. 

111. Inspect at least once a month for leakage in piston, valves and cocks. 
Watch gauge glass for leakage from hoiler when engine is not running. See if 
piston and valve rods are in alignment, if cylinder is scoi-ed, if all holts are 
secured, if slioulders are forming in tlie cylinder, if there is acid in the oil, etc. 

11. If cylinder, valve, rod or guide is scored, graphite \n\t <m will till the 
scratches and may restore the smoothness. 

V2. Always add oil to the graphite. 

13. Packing allowed to hecome hard will flute the rods. 

14. Packing, waste, iron parts, etc., temporarily laid on the floor, may carry 
dirt and grit to the hearing parts. 

1."). Every hearing surfac(> recpiires a drop of the best mineral oil applied not 
often hut regularly — a thick oil for cylinder and thin for other parts. Most 
engineers use too much oil. Never allow surfaces to get dry. Dirty oil from 
boxes luay be filtered and reused. 

Ki. Thin grease mixed with cylinder oil is th(> best lubricant for governors. 

17. If there is not a belt tightener, put the belt partially on the pulley at rest, 
then run it on the engine i)ulley to be started with very slow motion. 

1^^. The i)racticpd ear can generally tell if the exhaust is regular. If the puffs 
are long and short alternately, the exhaust is freer at one end than the other. 
One exhaust may be heavier, yet the two may be ecpially timed. Etpializing 
the cut-off and exhaust is a partial remedy. 

If). It is dilticult often to locate knocking. Therefore, seek the place and 
cause, but proceed cautiou.sly before making any changes intended to remedy 
the evil. It is iisually due to the following causes: 

ill) Lost motion in i-rank, cr<isshead, valve rods, main jonrnals, etc. Try the 
hand on the suspected jiart at rest or in slow motion. 

(b) Valve not set or the .slipping of eccentric which admits steam suddenly; 
if due to valve, an indicator diagram is necessary. 

(c) Engine out of line. See remedy elsewhere. 

((/) Crank pin not parallel to main shaft. Disconnect connecting rod from 
cro.sshead and clamp t > this end of the rod a sjtirit level ]»arallel with the sliaft. 
As the crank is turned tht> bulb will show if pin is not parallel with the .shaft. 

(c) Lt'aky piston rings, poor lubrication, water in cylinder. 

20. Relief valve on cylinder is set at 5 pounds higher than the safety valve. 

21. Heating is due to lack of good lubricant; dirt, grit, or filings in .iounials; 
bearings too tight ; reciprocating or revolving i)arts out of line ; improper fitting ; 
too heavy load ; too high velocity ; too great ])ressure. 

22. To feel for heating at crank i)in in motion, stand in front of the engine 
anil lower slowly the hand, palm down, ruitil the crank barely touches it on the 
up stroke; or. starting fr(5m the crosshead end of the connecting rod, slide the 
hand along the rod to the crank. 

23. Never permit the heating to reach a degree uncomfortable to the hand. 
If it remains moderate, oil and wear may stop it. 

1711— ■-'. 



18 



HANDBOOK FOR ELECTRICIANS. 



24. In case of smoke from overheating, slow down the engine as quickly and 
as far as possible, but do not stop it until the part has cooled. Then dismount 
quickly, clean off the brass from the steel, and correct 
the fault. 

25. Piston rin^s should clear the cylinder at both 
ends a fraction of their width for smooth running. 

26. Remember that the pump is a second engine. 

27. If a valve leaks, clean it, reground the seat, but 
do not increase the pressure. 

(C) THE CYIilNDER LUBRICATOR (Fill, 10). 

To refill with oil, close L, C and K in order. Unplug 
F to drain off reservoir, allowing air to enter at E. 
Close F and take out E to fill with oil. Replace E, 
open C and A', and regulate L from two to five drops 
a minute, depending upon the qualtity of oil and the 
amount of work. 

If a glass breaks, close C and K and drain out. 
Loosen the packing nuts, replace with new glass and 
gaskets, taking care that the glass does not touch metal. 

(D) THE FOUR CRITICAL POSITIOIVS OF 
VALVE AND OTHER MOVING PARTS. 

1. When, as in fig. 11, the valve Xis in the middle 
position, and the eccentric arm is nearly vertical, ^4 a 
is the steam lap and B b is the exhaust lap of the 
valve. The lead of a valve is the distance the steam 
port is opened at the beginning of the crank's str-)ke 
(fig. 12). Full port opening (fig. 15) occurs at the end 
of the eccentric's stroke. 

.... o..^,... ^. ^- ^^V' lead, or full port angle, or arc, is that made 

halV;'"or upper" vaWe'ri" fliifng by either crank or eccentric while a point of the valve 
plug ; F, drain ; A', discharge valve ; travels over lap, lead, or full port Opening. 
Ji'ass -^p S-feed'giass^' ^''"^*' ^- Travel = total distance valve moves = two times 
' ' ' length of eccentric arm. Stroke=total distance piston 

moves = two times length of crank. Angle of advance = amount of angle the 
eccentric is ahead of crank. 

4. If we consider what takes place at one port, say the left, and on the left 
side of the piston during one full stroke and return, it will be seen that there 
are four critical positions of valve, piston, etc., during the one turn of the fly 
wheel, say clockwise, as in figs. 13, 16, 17, 18. 




10. Sight Lubricator to 
Cylinder. 

iJ, reservoir, oil shown in upper 




i 1. Laps. 



(1) Admission of steam begins Avhen ^ is at a going to the right. 

(2) Cut off of steam begins when ^4 is at a going to the left. 

(3) Release of steam begins when B is at b, going to the left. 

(4) Compression of steam begins when B is at b, going to the right. 

These four events similarly occur on the right side during a stroke and return, 
and so on. 



THE STEAM ENGINE. 



19 



SLIDE VALVC 




12. Lead. 



Fig. 13 .shows admission of steam to lu-ad end of cylinder ])efore the end of a 
stroke, m order to torm a cushion. 




In fig. 14 the piston (also crank) is at head dead center under full boiler pres- 
.re, and valve is at lead by definition. 



'jy/^'.v.v////zz^^-i 




In fig. 15 steam port is full open. Eccentric arm is at crank dead center. 




In fig. 16 steam is cut off Pressure on piston will now be due to expansion 
only of the steam in the cylinder. Eccentric makes nearlv the same angle with 
vertical through O. as at admission. " 




20 



HANDBOOK FOR ELECTRICIANS. 



In fig. 17 inside edge of valve going to left has reached port's inside edge. 
Release of steam or its exhaust to atmosphere begins. 




17. 



In fig. 18 inside edge of valve going to right has reached the port's inside edge, 
and compression of steam in the cylinder follows. Eccentric makes about the 
same angle w^ith vertical through O as at release. 

Admission (fig. 13) next follows, and so on. 




(E) TO CONSTRUCT ACCURATEIY I:N^ ONE FIGURE (19) 
THE FOUR CRITICAL POSITIONS. 



Given, travel = 3 inches ; steam lap = li inches ; lead = ^l inch, and exhaust 
lap = i inch. 

On Hi = S inches, draw eccentric's circle m i n; outside, crank's circle M I N. 
O m is the eccentric arm's position at valve's mid travel. 

Lay off. O E = exhaust lap, i inch, O L = steam lap, L T = lead, erect verticals 
to get points d, c, a, 6, and t. The radii O a, O b. O c, and O d are by definitions 
the positions of the eccentric at admission, cut-ofif, release and compression. 

d 111 = c n = exhaust-lap arc ; m a = nb = steam-lap arc ; a t = lead arc. 

d O VI — exliaust-lap angle ; in O a = steam-lap angle ; a O t = lead angle. 

Lay oE H F — a t, and through F draw O A. AOa are the positions of crank 
and eccentric at admission. 

The eccentric is always in advance of the crank by an arc = m a + 90° + a t, 
or in angle = vi O a + 90° + H O F = angle of advance. 

Steam lap O L + full-port opening Li = ^ valve travel = li- inches; full-port 
arc a t = 90° — m a. 

Lay off from b, arc b x = m a + 90° + a t, or, since b i = ai = 90° — m a, lay 
off from i the difference (2 vi a -{- a t) to get x. Bob are the positions of crank 
and eccentric at cut-off. 

Lay off frcim c arc cy = m a -\- 90° -\- a t, or, since arc c i = 90° + c n, lay off 
from i the difference {m a + a t — d m) to get y. C O c are the positions of 
crank and eccentric at release. 

Lay off from d, arc d z = ma + 90° + at, or, since arc d H = 90° — d m, lay off 
from H the difference {m a -^ a t -\- d m) to get z. D o d are the crank and 
eccentric positions at compression. 

Thei't'fore the crank is — 

At admission, the lead angle distant from first dead center. 

At cut-off, two steam lap angles + lead angle from second dead center. 

At release, steam lap + l^ad — exhaust lap (angles) from second dead center. 

At compression, steam lap -\- lead -j- exhaust lap (angles) from first dead 
'"enter. 



THE STEAM ENGINE. 



21 




19. Four Critical Positions of Crank and Eccentric Arm. 



(F) TO EQUALIZE THE FORVVAKD AND RETURN STROKES 

OF THE PISTOX. 



The forec:oing would only be true for very long connecting rods. The angular 
po.sition of an actual rod (ahont six times longer than the crank) delays the 
events on the stroke from the head end and produces them too early on the 

return. If, for instance (fig. 20), the pis- 
ton is at. 1 and (' when crank is at the 
dead centers, it will be to the right of B, 
midway of .1 ami ( ', when the crank is 
vertical ; that is to say, the piston travels 
faster in the head end half. For a i)artial 
remedy eiiualize the leads of the valve and 
slightly alter one exhaust lap for e<iual 
release and compression. The valve position "is less disturbed than that of crank 
because the eccentric arm is relatively short. 




20. Crank Moves Uniformly, Piston 
Does Not. 



23 



HANDBOOK FOR ELECTRICIANS. 



(G) EFFECT OF CHANGING STEAM LAP, EXHAUST LAP, 
TRAVEL AND ANGULAR ADVANCE. 



By increasing. 



Steam lap 

Kxbaust lap 

Travel nr icoentric 

arm. 
Angular advance 



Begins later, ends 

sooner. 
Unchanged 



Begins sooner, lasts 
longer. 

Begins sooner, pe- 
riod same. 



Kxpansion. 



Begins sooner, la.st.s 
longer. 

Begins same, lasts 
longer. 

Begins later, ends 
sooner. 

Begins sooner, pe- 
riod same. 



Utichanged 

Begins later, ends 
sooner. 

Begins later, ends 
later. 

Begins sooner, pe- 
riod same. 



Compression. 



Begins at same 
point. 

Begins sooner, lasts 
longer. 

Begins later, ends 
sooner. 

Begins sooner, pe- 
riod same. 



(H) 



PRINCIPLE OF THE WHEEL-GOVERNOR AUTO- 
MATIC CUT-OFF. 



1. If the angle of advance A O a (fig. 19) is increased, fnll port L i is made 
less, l> approaches i, the cut-off h O occurs earlier and the period of admission of 
steam against the piston is lessened. But the lead would thereby be increased. 
To keep it the same, the eccentric arm is, by the automatic cut-off, shortened at 
the same time the angle of advance is increased. The valve travel is thus less- 
ened and the lead is preserved. 

Or, admission may be prolonged by automatically decreasing the angle of 
advance and increasing in effect the eccentric's arm. 

2. Wheel governors accomplish the 
above in different ways in order to keep 
uniform the speed under a varying 
load — 

(a) If load decreases, speed increases, 
governor weight is thrown out by cen- 
trifugal force, valve travel and admis- 
sion period are diminished. 

(&) If load increases, speed decreases, 
governor weight is drawn in by the 
spring, valve travel and admission 
period are increased. 

3. The governor (fig. 21) of the 
straight-line engine affords a typical, 
simple, and accurate automatic con- 
trol of steam to load. 

The eccentric is screwed to a plate, 
A C, pivoted at a on the fly-wheel, re- 
volving clockwise. As the weight W 
flies out, the end d of the eccentric 
arm is shifted about a as a center 
toward c by the links / 1 moving Avith 
the arrow against the spring S. Govern- 
ors usually have two opposite weights actuating the eccentric arm like the above. 
Fig. 22 gives by the same letters the relative positions above of crank h c. 

eccentric arm c d, center of shaft c and center of governor motion a. Angle of 

advance = li c d. Describe arc through d to center a. 

When too high speed throws W outward, the free 

end of the eccentric arm is moved to some point e, 

the angle of advance becomes h c e.and the eccentric's 

length c e. The valve travel is shortened, the lead 

is preserved, cut-off occurs earlier, admission of steam 

and speed are less. 

4. To adjust the governor for increase of speed, 
slide the weights, if movable, toward the center 
equally ; or tighten the springs equally ; note that the 
spirals do not touch each other. To run slow, loosen 
them, but seldom more than an inch. 

5. To make sure that the tensions on both springs remain equal, count the 
turns made by the nuts in tightening, or listen to the sounds of the springs when 
struck after tightening. 

6. For larger changes, procure other weights and springs. The governor can 
usually l)e changed to run reverse. If it ever works irregularly, look for a 
gummed or dry joint or a surface that binds. 




c A = general direction of 
c d ^ eccentric arm. 



L-rank and eccentric rod. 



\ 



i- 






22. Wheel Governor's Auto- 
matic Control of Steam 
Valve. 




22a. Sturtevant Double Engine. 



THE STEAM EN(;INE. 23 

(I) A FUI^L INSPECTIOX 1)F AN ENGINE. 

A full inspection extends to proving? the level of its base: the alij2:nment of 
cylinder, sliaft, crank pin and f^uides; of valve rod and eccentric: trneness of 
cylinder l)ore, tiy wheel, and hearintr surfac-es; eciuality of clearance; the fit 
of i)iston to cylinder; of crosshead to ;;uides: of connecting rod brasses to crank- 
pin and crosshead .ioiirnals ; of main shaft to its bearings ; of jjacking to rods ; the 
setting and critical positions of the valve; leiigths of rods and the general order. 

Tools required: Spirit level, inside calipers, plumb line, straightedge, ruled 
6(piare, very fine stout string, stick slotted for a cylinder-head bolt. The ri;le.s 
given below for a horizontal engine siaggest the course for a vertical. 

1. To prove the base level, ajjply the spirit level in two positions at right 
angles on the base, always reversing the level. 

2. To get the dead center, place a fine poiiiter from a fixed rest close to the 
fly wheeVs outer rim in front. Turn fly wheel to bring th(> crosshead to about 
i inch from the outer end of its travel. Mark accurately the guide at tlie end 
of crosshead and the rim opposite the pointer: 

Continue the turn of the engine until the same end of crosshead returns 
exactly to the mark on the guide. ^lark the jiointers place on the rim and 
turn the wheel so that the pointer stands midway of the two marks on the 
rim. The engine is now at its outer dead center. A fine straight line drawn 
on the guides along the crosshead end marks the position. Next find and 
mark the inner dead center. 

3. To line up an engine (horizontal) is to find if cylinder's axis prolonged inter- 
sects the axis of the main shaft at right angles, and the axis of the crosshead 
pin in all positions, and if the main shaft is level. 

Disconnect and remove all parts from crank pin to and including back cylin- 
der head. To any bolt of this head, l)olt the slotted stick across the head to hold 
one end of the fine string in the axis of the cylinder. Draw the string taut 
throiigh the cylinder to an adjustable upright in front of the engine. With 
inside calipers carefully adjiist the string to the centers of the two counterbores. 
This is the center line of the engine, to which other parts are adjusted. 

(«) Put one leg of the square against an inner crank face so that the outer 
edge of the other leg is in the shaft's axis See if the edge just touches the line 
as the crank is tunied. 

(b) To S(iuare the shaft, turn the crank pin forward so that it almost touches 
the center line of the cylinder. Calijier between line and crank or disc. Turn 
crank pin backward to line and likewise caliper. If the two distances are equal 
the shaft is scjuare. If not stpiare, move the out-end jnllow block. 

(c) To level the shaft, ai)ply the spirit level on top and reverse it. Or. better, 
drop a i)lumb-line in front of the crank face and caliper at the up .and down 
half stroke similarly as in squaring. If th.e shaft is out, shift it by liners, babbitt, 
thicken or thinner "brasses, or by using a file, as re(|uired. 

To verify both the level of shaft and trneness of fly wheel, drop a plumb line 
from the ceiling past the wheel's outer rim and center and turn the wheel. 

(d) To line the guides, lay a straightedge across the two guides and caliper 
between it and tlie center line the whole length of the guides. Likewise caliper 
between line and the inside edges. Measurements will show if center line inter- 
sects the axis of the crosshead pin. If necessary, dress the guides with file or 
sanditaper, or insert shims. 

(c) To verify (?> and (l).'key up the connecting rod sniag to the crank i)in. and while 
turning the crank see if the free end of the rod moves i)arallel ^\^th the guides. 

4. To align valve rod and eccentric, less liable to derangement, will require 
like expedients. 

5. To find whether cylinder has worn out of true, cali])er all around tlie center 
line in one circle, then another, and so on along the inside of the cylinder. 

6. To test the fit of the jnston : (a) Loosen the connecting-rod keys, and, by 
filming the fly wheel, bring tlie ])i.ston to the head end. Take otf cover, also 
the follower on the i»iston, and .see that the piston rings press against the cylin- 
der bore all around witliout binding. 

{b) For a check, put the engine to the other dead center and admit a little 
steam. Leaking, it' any, can be seen at the o])en end. 

(o) Or, without removing the head end. if the cylinder is piped for indicator, 
relief valve, or exhaust to air, tru-n crank to either dead center and open the 
cock at the end oppo.site from that at which steam is very slowly admitted. 
Steam will aiipoar at tlie cock if the juston leaks. 

{(I) The split of a ])iston ring is down in a horizontal engine. If two rings, 
they break joints on the lower half. 



24 



HANDBOOK FOR ELECTRICIANS. 




THE STEAM ENGINE. 



25 



7. Tlic croHshcad. — It is: essential to keep the iiiston rod exactly in the center 
line. Give the gibs an easy sliding tit without lost motion. Ease away on the 
crosshead pin inside the connecting rod to prevent undi;e wear (fig. 24). 

8. To get the trxie length of connecting rod: (a) Move piston, with cros.shead 
disconnected, against one cylinder head, i. e., the striking point, and mark the 
guide opi)osito crosshead end. Do the same for the otlier head. Sni)pose the 
distance lietween both guide marks = 25 inches; between centers of erank i)in 
and sliaft = 12 inches. Tlien full stroke = 24 indies, and clearance at either 
end = A inch. Now move crosshead A inch bac-k from the striking point 
mark, bring craidv to dead center, and with a tram measure between the outside 
centers of crank i)in and wrist pin for the required length. 

(b) Ti> lengthen the rod insert liners between its bra.sses and stud ends. 

(c) To put on the rod move the pi.ston .slightly toward the crank and ad.iust 
the keys so that the bores of the brasses easily lit without play. 

((/) To take up lost motion loosen the set screws, drive down the key, and 
tigliten the .set screws. It is a good jilan to drive in the key until the bras.ses 
liind, mark the key and slide it back to a proper fit, marking it again for later 
ad.iu.stment. if necessary. 

(c) To ei^ualize clearance, usually J to i inch, in the cylinder, lengthen or 
.shorten the connecting rod. 

U. To adjust main shaft bearings, the shaft is shifted on either side, or both, 
by the u.se of thicker or thinner shims. ])abbitt or brasses. If the brasses meet, 
tigliten the nuts to an easy bearing. If nc.t. lay in a sufficiently thick wire of 
lead to take the compression and screw the nuts to a lieariiig. Then replace Ijy 
a .-^him gauged to the same thickness an<l screw the nuts home. 

If the lead wire is thicker at one end, the shim will be made the same. 

1(1. To set a common slide valve, is to make the leads at both ports equal, and 
the full-i)ort openings as nearly eipial as po.s.sible. Leads are made c<iual or 
une(iual by changing valve or eccentric rod's length ; Init if both leads are equal, 
change of amount is gotten by changing the angle of advance. Always com- 
pare the openings by inserting a long, thin wedge. 




i 




y^^ 



^^ 



23. Armington & Sims D. C. Set. 

((/) Take off the steam-chest cover (fig. 2:}), give all connections a close working 
fit, i)lace crank ;it either dead center, and measure the lead for ea<'h port ; if the 
leads are etpial to each other and to the amount given by tlie l)uilder. tlie valve 
is properly .set. If not. change the valve rod's length by the half difference, and 
re])eat the oi)eration, which will ])robably first reriuire a change of the eccentric's 
position to bring the lead right at the first dead center. 

Suppose the valve has jiroper lead, ,',. incli with crank at first dead center, and 
shows a lap of ij inch at the other jiort with crank at second dead center, the 



26 



HANDBOOK FOR ELECTRICIANS. 




tan — u3 — o" 



THE STEAM ENGINE. 



'27 



valve rod's length is then changed by v? inch. Now i)ut crank at first dead 
center and change eccentric's position to give -f',.-inch lead and move crank 
(always in its working direction) to second dead center, and so on. 

(b) If the valve is controlled hy a wheel governor, block the weights ont to 
their positions at normal speed and proceed as above. Both length of rod and 
angle of a<lvance are successively changed in setting valves. 

(c) In vertical engines with cylinder above, the lead at the crank-end port is 
given slightly increased lead over the iipper to compensate for weight of moving 
parts and the wear downwards. 

(J) TO PACK THE PISTON HOD. 

(1) Cut the rubber or other material into four or more rings of square cross 
section with beveled split to tit rod and box so closely that the finger can ]tush 
them into place. The first .split is up; the others, break joints. Rub grai)hite 
or chalk on the outside to i)revent its sticking to the iron. 

Screw down the gland evenly, first one nut a partial turn and then the other 
a little more, and so on alternately. 

(2) To stop a leak, tighten little at a time. If several trials fail, reverse the 
]>acking, or, l)etter, renew with soft i)acking always kept in stock. 

(3) The troubles with packing result from ill-fitting rings, engine out of line, 
rough rods, not correcting the first small leak, too long or too short or too few 
rings, or too small stuffing box. The valve rod is similarly packed. 

(K) THE PISTOX VAIiVE IN COMMON USE IS 
BAI.ANCED. 

This valve is cylindrical and iisually hoHow. Steam passes over its edges on 
all sides aTid does not force the valve against its seat with unnatural i)i-essure 
as in the case of the D-slide valve. Its action is precisely the same and the fore- 
going principles apply, whether the piston valve admits steam at the ends of the 
chest and exhausts at the middle, or admits steam from the middle around the 
valve and exhausts at its ends. 




24a. The Cylinder and Valve. 

To the latter chiss belongs the valve (fig. '24a) of the Armington & Sims 
engine, shown in the lead position. Live .steam surrounds the valve and 
fills its interior through one or the other of its end oi)enings. Steam has 
already started into the head-end i)ort from the niiddl<> of the chest and from 
the interior of the valve by way of tlie right-hand oi)ening. The exhaust 
occurs (juickly at either end of the cylinder through direct pa.ssages. The valve 
carries check rings at both ends. 

Tlie Rites governor (fig. '24h) is extremely simple, .sensitive and powerful. 
The eci-entric arm at its greatest elojigatiou is .slmrt. so tliat tlir valve's travel 
is small. The cut explains better than words its mode of operation. 



28 



HANDBOOK FOR ELECTRICIANS. 




24b. A. and S. Governor. 

The main journals have chain continiions oilers ; the crank pin, a centrifugal 
oiling device ; and the crosshead runs in oil, all supplied from a central reservoir. 
There is no throwing of oil. 

Fig. 22o shows the new Armington & Sims wheel governor and its con- 
nection with the valve. 




24c. End View Oiling Device, 



in.— THE HORNSBY-AKROYD OIL ENGINE 



Has HO ignition appai'atns anil is, when properly attended, reliable. One 
pint kerosene maintains one horsepower for one hour. 

(A) THE ENGINE. 

1. The enfi:ine (fig. 2G) is fo\ir cycle, i. e., in its pi'opiilsion four different 
operations ot-cur behind the piston in the four strokes which cause two complete 
turns of the pulley. They are — 

First strohr. — Admission (or suction). During the first outward stroke air is 
drawn into the cylinder and a thin, momentary jet of kerosene oil i:. sprayed 
into the adjoining hot combustion chamber or vaporizer (fig. 2Go). 

Second stroke. — Comjn'ession. In the folloAvnng inward stroke the air is driven 
through the narrow neck into the vaporizer to form with the oil vapor a mixture 
which at the end of the stroke is ignited by the heat in the chamber. 




f^au de Rochas Cvcle of H 






and most Explosive Engines. 



Tliiril stroke. — Explosi(3n plus expansion of the gas through the neck into the 
chamber then drives the piston outward with a maximum pressure of 130 
pounds i^er square inch and a mean of 40 to 75 pounds. 




-^-■J W/^-r..s 'j^-y:.v.'VMMy^.Mm 










^:]~B 



26a. 

Fourth stroke. — Exhaust of the products of combustion from the cylinder into 
the exhaust chamber and pipe occurs during the next inward stroke, or final 
cycle. 

During the first outstroke the thin stream of oil is instantly vaporized on 
striking the heated interior surface of tlie vaporizer, and the proper amount of 

(29) 



30 



HANDBOOK FOR ELECTRICIANS. 




THE HORNSBY-AKROVD (^IL ENGINE. 



31 



air heated en route by the hot exhaust chauiber, is drawn into the cylinder. 
Mixture and compression follow on the following; instroke, at the end of which 
ignition is caused by the heating effects of compression, friction, and vaporizers 
comlnned. The impulse is given only during one stroke in four. The vapor- 
izer is protected from cooling air currents ])y the hood, and its heating is con- 
trolled by the damper on top. Cylinder and valve box are cooled by a water 
jacket. 
2. Number and names of parts : 



CylindiT liner. 
CjiiiiiitT rasing. 
Viii)oriziT. 
Viiporizcr cap. 
Va|)oriziT-c!ij> joint rinR. 
Vaporizer cover. 
Va|K)rizer-cover lid. 
A'aporizer-cover tillin;; piece. 
Valve-box journal. 
Valve-l>ox sleeve. 
Spniy nozzle. 
Horizontal valve. 
Horizontal-valve spring. 
Vertical valve. 
Vertical-valve spring. 
Valve liox. 
Valve-box screw cap. 
Valve-box coupling. 
Overtlow glass. 
Half union, 
(lil-punip can. 
oil-puMip ping, 
dil-punip jilunger. 
(>il-pun]p Jilunger spring. 
Oil-punip Jilunger lock nut. 
Oil-jiunip Jilunger head. 
Oil-jiunij) Jiltinger-heacl guide 
Oil-jiUMip gauge. 
Oil-jiunip body. 



3<i. 


Oil-jmmji gland. 


58. 


31. 


Ifed jilate. 


69. 


32. 


Hearing cuji. 


CO. 


•M. 


Sjilasher. 


61. 


■M. 


Oil tank. 


62. 


■A:k 


Oil filter. 


G3. 


■W. 


Kilter cock. 


64. 


37. 


Worm gear. 


65. 


■AH. 


(iear wheel. 


66. 


3it. 


Gear guard. 


67. 


40. 


Crank shaft. 


68. 


41. 


Cnink-jiin oiler. 


69. 


42. 


Oiler elbow. 


70. 


43. 


Piston. 


71. 


44. 


Piston rings. 


72. 


45. 


Wrist jiin. 


73. 


46. 


Connecting rod. 


74. 


47. 


Connecting-rod lieml end. 


75. 


48. 


Connecting-rod crank end. 


76. 


49. 


Compression plates. 


77. 


50. 


Cam shaft. 


78. 


51. 


Governor wheel. 


79. 


52. 


Governor pinion. 


80. 


53. 


Governor-gear guard. 


81. 


54. 


Governor bracket. 


82. 


00. 


Governor si>indle. 


83. 


5(!. 


Governor counterpoise. 


84. 


57. 


Goveruor-couuterjioise lever. 


86. 



Governor balls. 
Governor counterweight. 
Governor-counterweight lever. 
Governor-regulating jilate. 
Governor fork. 
Governor-fork spindle. 
Governor connecting rod. 
Governor conuecting-roil lever. 
Valve lever. 
Air-valve cam. 
Exhaust-valve cam. 
Cam rollers. 
Lever fulcrum. 
Lever-fulcrum pin. 
.•\ir-valvo lever. 
Kxhaust-valve lever. 
Cam shifter. 
Locking handle. 
Air-exhaust valve box. 
Air-exhaust valve-box cover. 
Air-exhaust valve sjiring. 
Air valve. 
Kxhaust valve. 
Cylinder lubricator. 
Cylin<ler-luliricator cover. 
Ovlinder-lubricator j)ullev. 
Fiy wheel. 
Fly-wheel key guard. 




27a. Cylinder End Projection. 



32 



HANDBOOK FOR ELECTRICIANS. 




THE HtmX8BV-AKKOYD OIL EN(J1NE. 



33 












34 



HANDBOOK FOR ELECTRICIANS. 



3. The oil pump (fig. 28), iictuated by the same lever as the air-inlet valve 
(fig. 30), performs thedoiible ofifice of suction on the upstroke and of forcing on 
the downstroke. The suction as well as the forcing side has two check valves 
in series for certainty of action. On the downstroke oil is forced direct to the 
valve box. 

4. Valve box (fig. 29). — Here are two valves, ^the "horizontal" or check valve 
for keeping the oil from flowing back and preventing the possibility of prema- 
ture explosion, and the "vertical" or by-pass valve for regalation. 





HOR.nVlve. 



Oil Pump. 



29. Check and Bv=Pass Valve Box. 



5. The regulation of the engine is effected by altering tlie supply of oil in two 
ways: first, bv changing the length of stroke of the pump, i. e., the oil supply, 
and, second, jiutomatically by a sensitive ball governor which opens the by-pass 
valve in the valve box, and deflects a portion or all of the oil jet from the vapor- 
izer through the overflow outlet back to the tank. During the piston's first or 
suction stroke the pump injects the oil (opening the ' ' horizontal valve " ) through 
the spray nipples (see "oil jet," fig. 29) into the vaporizer : but if the by-pass valve 
is partially or wholly depressed at this time, part or all of the oil will overflow. 

6. The air-inlet and tlie exhaust-poppet valves (fig. 30) close at tlie proper 
times the exhaust chamber to their respective pipes. Always under the tension 




30. Exhaust=Chaniber Side of Engine. 



THE HORXSBY-AKROYD OIL ENGINE. 



35 



of sprin,ii:s they are actuated l)y levers moved by cams on the auxiliary shaft. 
ThnniKh the port (marked in the figure) leadiui,^ from the exhaust chamber to the 
rear interior of tlie cylinder, the air passes on 
its way in and the exhaust products on their 
way out. 

8. Fig. 'iOn gives the crank positions at the 
instants when the i)oi)pet valves oi)en and close. 
The air valve closes just after the crank has 
jias.sed out-center. The exhaust valve oi)ens at 
about 8.") per cent of full stroke and closes just 
after the air valve has opened. 

9. The jnston (fig. 2ib) shotild make a good 
fit top and Ijottoni, and not rub hard on the 
sides, as ascertained by inspection and turning 
the fly wheel. The three or five rings l)reak- 
ing joints on the underside must not leak. Their 
close fit and the g(»od lubrication of the piston 
are absolutely es.sential. Mechanical or sight 
feed lubricator is always used. • 




30a. 



(B) T]XGIXE-R()OM IXSTTJT CTIOJ^S. 



1. Before starting see that oil and water tanks (fig. 31) are full, and that the 
three cocks which sup])ly water to the water jackets are fullj' open. 

2. Hi'dtiiKj the vaporizer. — Fill the lamp witli oil otitside of the engine room, 
to avoid smoke, and put a piece of wck into the cups which are formed round 
the pipes. These wicks which should consist of a iDiece of ordinary asbestos 
stacking, will last for several weeks. 

c 




31. Water-CoolinK Connections. 

A little kerosene should then be jioured into the cup niider the coil and lighted. 
When this is nearly Imrnt out. pump uj) the reservoir with air liy tlie air pump, 
when oil vai)or will issue from the small nozzle and give a elear flame. Then 
lilace the lamp on the stand so that the coil is one-half inch from tlie vaporizer. 
Turn the damper for draft. 

When it is required to stop the lamj), turn the little thumbscrew on the reser- 
voir-filling nozzle, and let the air out. Should at any time the nozzle, where 



36 



HANDBOOK FOR ELECTRICIANS. 



the vapor comes out, get choked up, it can be cleaned with the small prickers 
which are sent for that purpose. 

The heatint>' up of the vaporizer is one of the most important things to be 
attended to, and care must be taken that it is made hot enough at starting. 
The attendant must see that the lamp is burning projierly, and that a good clear 
flame is given off from five to ten minutes according to the size of the engine. 
If, liowever, the lamp is burning badly, it may take longer to get up the proper 
heat. It is most important that this should be carefully attended to, as, though 
the engine may start if the vaporizer is not as hot as it ought to be, the engine 
will run badly, and perhaps soon stop altogether. Failure to get engines to run 
properly can in most cases be traced to the above. 

If the vaporizer is i^artly jacketed, close the valve on the inlet w^ater pipe 
before heating wp, and open or partially open while running. 

3. Oiling. — See that the oil cups on the two main crank-shaft bearings are fitted 
with proper wicks and filled with oil. Adjust the lubricator of the large end 
of the connecting rod and oil the small one which is inside — also the bearings 
on horizontal shaft and the skew gearing — the rollers at the ends of the 

valve levers and their pins, and the pins on which 
the levers rock — the governor spindle and joints, 
the bevel wheels wdiich drive same, and the joints 
that connect the governor to tlie small relief valve 
on the vaiiorizer — twenty places in all. For such 
bearings none but the best engine oil should be 
iTsed. Oiling should always be done during heating 
up the vaporizer, and the lamp should be left burn- 
ing for a few minutes after starting. 

4. To start. — Turn the small regulator on the 
governor bracket (fig. 276) to position "Shut," and 
work the pumji lever up and down until oil is seen 
to freely pass the overflow glass. Then turn the 
small regulator to position "Open," work thepumi> 
lever up and down again one or two strokes, then 
give the fly wheel one or two smart turns, when 
the engine will start readily. The engine will 
often start better by first tiTrning the fly wheel the 
reverse way, when an explosion will sometimes be 
obtained which will start the engine, and in any 
case the rebound thus obtained from the com- 
pressed air will help the fly wheel to be turned forward more easily. 

The handle upon the cam shaft, before starting engine, must be placed in the 
position marked "To start, "in order to relieve a part of the "compression," 
and immediately the engine has got up sufficient speed to affect the four cycles 
this handle should be placed in position marked "To work." 

No time should be lost in starting the engine after tlie vaporizer has been 
sufficiently heated, as the engine will not run satisfactorily if the vaporizer is 
allowed to cool down after heating it. If too much oil is pumped into vaporizer 
it will be difficult to start up. 

Starting gear is not necessarily required except for the larger engines, say 
35-h6rsepower and upwards ; 35-liorsepower engines can, however, be started by 
two men. Release the air from the lamp directly the engine starts. 

In tui'ning over the fly wheel there is a certain knack by which a skillful 
engineer exerts his force only once or twice, and usually on a certain one of the 
spokes ; it is the one which he reaches by stooping down to effect the compres- 
sion. If the engine starts in the wrong direction it will generally reverse itself 
after a few turns, when give it assistance. To avoid accident, never put a foot 
or a leg on a spoke to assist in starting. 

5. Failure to start is generally due to vaporizer not being hot enough (barely 
perceptible red in the dark). If the oil tank is full, if piston is clean, and if 
reheating the vaporizer again fails, examine the engine: 

(a) Oil pump. — Turn the regulator to "Shut" and work the pump by hand as 
in starting to see if a full stream of oil free from air, passes the glass as it 
should do. 

(6) If the stream is not a full one, open the three-way cock from oil reservoir ^ 
if oil flows out freely the filter is in order. If not, clean it. 

(c) If the pump is still unsatisfactory, see if air is in the iiump or pipes by 
disconnecting the oil-supply pipe from the vaporizer valve box, immping until 
oil overflows, then pressing left thumb tightly over outlet, jjump down once 
quickly. If the pump plunger yields, air is in the pipes. Or, pump several times 




32. 



THE IIOKXSUY-AKROYI) OIL ENGINE. 



37 



quickly and then remove the thumb suddenly ; if air is in the pipes, its elastic 
force will cause a loni^ jet (tig. 'S'2(t). 

{(l) If tliere is no air in the pipes, inspect the action of the valves by pressing 
the pump steadily down while closing the outlet with the thumb. If the plungt-r 
yields under a steady i)res.sure])ut nut under a sudden jerk, the suction v;ilves 
are not tight. To stop leakage, wash out valve 
boxes with oil ; if this fails, tap the steel ball 
valves <m their seats with a copi)er ])uncli. 

(c) To examine the vaporizer valve box, 
take it off, reconnect it with its pipe, stroke 

the ])ump as in regular working and observe I I H: ^'"'"^ A 

the jt't. If tlie jet is full, positive and clear, 
and l)egins with the downstroke and does 
not dribble after the the end of it, the jet is 
•normal — a very important conditicm. Watch 
the effect of partially and wliolly depressing 
the vertical valve while pumping. 




32a. Pump Detached. 



(a) Good action recpiires three things — 

(1) Oil and air delivered to vaporizer in 
right amounts at tlie right time. 

(2) Sufficient compression of the mixture before ignition. 

(3) Ignition of gas complete at the ])roper time. 

{b) Rcguldtioii. — (1) When the engine is wi>rking at its full power, the dis- 
tance between the two round tlauges on the pump plunger (tig. 28) should be 
such that the hand gauge will allow the part stamped '• 1 " to just fit in between 
the flanges; and if at any time the positions of these flanges be altered, they can 
always be readjusted to "this gauge. The other lengths on the liand gauge are 
useful for adjusting the pump to economize oil when runiiing on a me(lii;m 
load ■•2"' or a light load '"3" of tlie gauge. Still, familiarity with an engine is 
better than the gauge for regulation. If overflows show of tener than once in 
5 or strokes, the pump stroke may be shortened. 




32b. Governor With Overflow Glass. 

(2) The governor (fig. ;i2/i) is adjusted to reduce the oil jet occa.sionally. At 
normal speed it revolves about i ineh clear of its .seat. When it runs too fivst 
its connecting mechanism depresses the verticil valve and diverts more (U- less 
oil to the overflow. Moving the weight out from the fulcrum slows tlie gov- 
enKU's action. "Governor hunting." causing the engine to run unsteadily, is 
due to joints or .si)indle beeomiiig bent, dirty or sticky. 

When engines are re(piired to run empty or light, it is best to alter the stroke 
of the ]tnm]) to just the amoniit of oil that will keep the engine running, and 
can even be rciluced so that tlie speed of the engine is a few revolutiojis under 
the usual speed (so that the governor can not cut out any oil, whieh allows the 
vapcn-izer to get a small charge of oil each time), and thus keep it from getting 
cooled downi. Also the cock on the return or lower water circulating pipe and 



38 



HANDBOOK FOR ELECTRICIANS. 




32c. 



the cylinder jacket can be nearly closed, so as to keep the cylinder warmer. 
The above remarks do not apply when the work is intermittent, and the engine 
is not running light very long together. 

(c) In the valve box (hgs. 27b, 29), if the horizontal valve is not working prop- 
erly, vapor from exijlosion will be found passing the overflow glass whenever the 
little lever or the finger presses down the vertical valve. Unscrew tlie cap and 
turn the valve by its tail around to dislodge any dirt in the seat of the valve, 
and see that the spring is closing the valve. If this does not stop leaking, take 
out the valve, ground it on its seat with a little emery flour and water, and 
take care in replacing valve and sleeve to preserve the same thickness of jointing 
material, and hence same valve opening. 

(d) The spray hole or holes (figs. 27b and 29) are liable to get clogged. The 
valve box is taken off and each hole is cleared by the little wires supplied for the 
purjiose, so as not to increase the size. 

((') If the pipe to the vaporizer valve box does not rise all the way from the 
pump, or if it gets bent down, an air pocket will be formed in which air will be 
compressed upon each stroke of the pump, and thus allow the oil to go in slowly 
and not, as it should do, suddenly. Also if the oil tank gets emptied of oil at 

any time, air will get into the suction 
and delivery pipes of pump, and it will 
take some time before the oil going through 
the pump and pipes will get rid of this air, 
so that for a while the engine would not 
work properly, as the air. by getting com- 
pressed as the pump works, will interfere 
with the oil being pumped in suddenly, as 
it should be. It is best, if ever the oil gets 
below the filter in the tank, to work the 
pump by hand for say ten minutes, hold- 
ing open the relief valve on the vaporizer 
valve box so as to get air well out of the 
pipes. Derangement of the pump rarely 
occurs. If the packing is renewed it should not be screwed so tight as to bind 
the plunger. 

(/ ) Tlie air inlet and exhaust poppet valves (fig. 32e) must always work freely 
and definitely and drop on to their seats. They can at any time, if required, be 
made tight by grinding in with a little flour of emery and water. The set screws 
(fig. 82d) at the ends of the levers that open these valves must not be screwed up 
so high that the valves can not close; this can always be ascertained by seeing 
that the rollers at the other end of the levers are just clear of the cams, that is, 
when the projecting i)art of the cams is not touching them. 

(g) Cylinder's proper temperature lies Itetween 110° and 130' F. The cooling 
tank is kept full of fresh water below 120° F. If the temperature tends to rise 
above this, cold water must be added, or a 
pump capable of delivering 10 gallons per hour 
l^er horsepower of engine is connected with 
the shaft to maintain from another source cir- 
culation around the cylinder. If a cheap sup- 
ply under pressure is available, use it. If the 
supply is above 70° F., as at many southern 
posts, much more water will be necessary. 
Sea water, if unavoidable and if circulated 
rapidly, can be used, but the water jacket 
should be watched for deposits. 

(/(.) If the piston gets black and gummy, or 
the exhaust gases are like smoke, or "cough- 
ing" is continuous, combustion is incomx)lete, due chiefly to excess of oil or too 
little air, or possibly to leakage over the piston rings. 

(i) Ignition can be retarded by lessening the vaporizer's heat and slightly 
reducing compression by increasing the clearance in the cylinder. In starting 
or on light loads the water inlet to valve box may be partly or wholly closed to 
preserve the vaporizer's temperature. 

{j) Heat in exhaust and vaporizer valve boxes sometimes causes the valves 
not to seat or their stems to stick, and necessitates regrounding. 

(k) If a little oil is sent into the heated vaporizer and the fly wheel is turned 
forward, the engine should start freely. If not. test the spray by hand and turn 
the fly wheel backward to test the compression. If this pressure is so slight 




32d. 



THE HORNSBY-AKROYD OIL ENGINE. 



39 



(the relief cam being out of action) that it can be overcomo by hand, there is 
leakage in the piston rings, the air or exliaiist valve or some joint or gasket. 

(I) Watch the temperatures and oiling of bearings, especially of tlie cylinder; 
use just enough oil for the load and listen for regular action after fifteen min- 
utes' run ; keep every part clean. 

( ?H ) For sul jsequent reference in time of trouble, mark on the gearing or record 
w-hen engine runs well, the exact positions of crank when the popjiet valves open 
and close and for load and half load, or the usual load after an li(>ur"s satisfac- 
tory run, the motion of pump stroke, heat of outlet water, frequency of oil over- 
flow, governor's rise, vaporizer's color in the dark, appearance of exhaust and 
piston. 

(h) The engine is working efficiently if, after getting warmed up, it runs on 
its load smoothly to the eye and ear. if the piston .shows no carbon deposit, if 
tlie exhaiist ga.ses are invisible or nearly so, and if the explosions sound regu- 
larly, except occasionally when the governor reduces the explosive charge. 




STt)I>PIN(J. 

(a) Turn the small regulator on the governor bracket to position marked 
"Shut." To stop quickly, hold down the air-valve lever at the same time. 
If the engine does not then stop readily, the spring of the horizontal check 
valve is weak and oil is entering the vaporizer instead of all coming thi'ough 
the overflow A^alve, as it sliould at "Shut." If the stop is for a brief period, but 
more than five minutes, it will be necessary to start the lam]) iinder the vaporizer. 

(h) In frosty weather do not omit, 
before leaving the engine, to run all 
water out of the piju'S and water jackets 
V)y first closing the main water-jiipe cock 
and opening the floor cock. The small 
water cocks to the valve-box water jacket 
are usually left open. 

Fitmlainoital Alterations. — (a) If 
air or exhaust valves appear to be o])en- 
ing or closing at the wrong time, take 
off the nut on the end of the lay shaft 
which liolds the skew when on. and see 
that the chisel cuts on the .shaft and on 
the skew wheel are opposite to one an- 
other, as shown in fig. 'S'.^. Ihe lay 
shaft is coned where the skew wheel is 
fixed, and is held on sim]>ly by fric- 
tion, the nut being tightened against it. 

Slmuld it at any time bo neces.sary to 
take out the crank sliaft, always be sure 
that the skew wheel gearing is ]iut 
together so that the tooth marked (> 
on the crank-shaft skew wheel fits in 
between the two teeth marked () on the lav 
sketch (fig. 33). 

(b) To reverse the direction of rotation, exchange the relative positions of the 
cams actuating the air an<l exhaust valves and the fuel supply. 




33a. Belt Pulls on Lower Run. 

shaft skew wheel, as shown on the 



40 



HANDBOOK FOR ELECTRICIANS; 




THE IIORXSBY-AKROYD OIL ENGINE. 



41 




Fig. 38a gives also the positions of the crank at the moments when the air and 
exhaust valves open anil close. 

The pressure in the cvlin(l(>r iluring four consecutive strokes and the impor- 
tant action of valves and other parts and the time of ignition during a run, 
can best he seen by means of cards taken with 
the Crosby or other indicator (fig. o4). If these 
show faults, adjustments may be made to correct 
them. Unless the indicator is properly set, its 
drawing will be misli-ading. The cut shows its 
attacljment to the engine and the means for get- 
ting tl-.e brake horsepower and the amount of oil 
consumed. 

All cylinders are tapped for indicator tests. 
The operation is similar to that for steam engines 
and the importance of getting a correct card is 
even more imi)ortant. 

In the A card ignition took place slightly l)efore 
the piston reached the end of its stroke, and the 
pressure during the first third of the ex])ansion 
stroke fell olf too rapidly. The exhaust was not 
free and the compression was too great. 

Diagram B shows good action on a load. The 
ignition line should be nearly perpendicular to the 
atmospheric. The exhaust 'opened at 90 per cent 
of the full stroke, and the pressure during exhaust 
and suction was 0. There is good area ])etween 
the exjiansion and compression lines, and all lines 
show steadiness. 

In the third card C the suction line below the 
atmosphere indicates that the inlet of air was 
hindered. The low compression line points to 
leakage past the poppet valves, oil inlet, or 
piston. From the waving in the lines and short- 
ness of figure, the indicator may not be in proper 
order. 

In the D card the events are lettered in the 
order of occurrence. The exhaust was c.ioked, 
and ignition took place too early. Compression 
began too soon and became too great. 

Full directions for erecting, testing, installing, 
remarkable engine will be found in Groldinghams 
the above cuts are taken. 




running, and repairing this 
"Oil Engines," from which 



IV.— THE DYNAMO. 




Magnetic Wind From 
N. to S. Pole. 



(A) GENERA!^ PRI:N^CIPLES. 

The short exploring magnetic needle will show that the space, or field, between 
the poles of a horseshoe magnet has the strongest magnetic force and that the 
imaginary lines therein which represent the direction and intensity of the force, 
are approximately straight, parallel and uniformly distributed (fig. 35). 

I. Laws of the induction of an electromotive force in a loop are as follows : 

1. Induction. — An E. M. F. is induced or generated in a 
coil Avhenever the number of lines of magnetic force 
through it is changing — either increasing or decreasing — 
by the motion of the coil or lines, or both. 

2. Direction. — Its direction is clockwise when the num- 
ber of lines through the coil is decreasing and contra- 
clockwise when increasing — this to a person looking at 
the coil from the side on which the lines enter it. 

3. The amount of induced E. M. F. varies directly with 
the time rate (i. e., the rapidity) of change of the num- 
ber of lines inclosed by the coil. 

II. Or, the laws may be otherwise stated for any 
straight conductor as, for instance, any short length of 
a loop : 

1. An E. M. F. is induced in any conductor while it is 
cutting across lines of magnetic force, by the motion of 
the conductor or of the lines oi of both. 

2. Hold thumb, forefinger and middle finger of the 
right hand, each at right angles to the other two. If the 

middle finger represents the conductor, if 

the forefinger points in the direction of 

the lines of (fore) force, and if the thumb 

points in the direction the conductor 

moves, the middle finger will point in 

the direction of the induced E. M. F. 
3. The amount of E. M. F. induced varies 

directly with the time rate (or rapidity) 

with which the number of lines of force 

is ciit. 

III. An alternating current is usually 

generated in a revolving loop. The nega- 
tive part can be rectified in the outer 

circuit. 
1. It follows from either set of the above laws that if the coil in fig. 37 revolves 

uniformly as the brushes point, and if the external circuit is closed, (1) a current 

will be generated in the coil due to the induced E. 
(2) Its direction, during the entire half revolution of 
which the coil's position is shown in the figure mid- 
way, will be toward the brush marked -f- ; in the 
next half revolution, to the other half. (B) The 
current strengths will be great- 
est at both vertical positions, 
and Oat both horizontals, where 
their direction is reversed. 

2. The current. ortheE.M.F., 
induced during little more than 38. 

one revolution, is expressed by 

the curve in fig. 38. That part of the curve below the reference line represents 

tlie negative C generated. 

3. The negative C may be rectified, i. e. , so turned as to go to line as a positive 

C, by the device of a 2-part commutator (fig. 39) in place of the two rings of 

(42) 





The Tliree Positive Directions at 
Right Angles. 





37. Simple A. C. Dynamo. 



THE DYXAAIO. 



43 



40. 



fig. 37. The two parts of the coinmutator are the terminals of the coil, and 
so disi)osed that each hrnsh shall pass from one part to the other at the instant 
the indiiced ci\iTent chanji;es or is zero. This is the simplest form of a direct 
enrrent, self-exciting dynamo, such as the fnse- 
firint^ dynamo. 

4. The current thus sent to the field and the 
external circuit consists of positive pulsations or 
waves, shown in fig. 40. 

5. In order to render the 

positive waves less abrui)t, 

that is, to make the dynamo 

current more nearly like a 

battery current rein-esented 
by the broken line in fii^. 40, it is only necessary to 
iucrea.se the number of armature coils and of com- 
mutator strijxs. 

6. Priiiciph' of self-e.x'cithuj r///«a;»o.s. — There is 

u.suallv sufficient magnetism in the field of the ,„ c:„„i„ n r n..-„ 

-, . • ^ , , ^° . . . . ,, 39. bimple U. C Dvnamo. 

soft-u'on held magnet core to give rise to a small 

current in the armature coil wlien revolved. This current flowing, wholly or in 
part, througli the winding of the field magnet, increases its magnetism and 
therefore the number of lines of force in tlie field between the i)oles. The cur- 
rent in the armature coil thereby is increased, and so the oi)eration continues 
mtil the magnet is saturated and the dynamo gives its full cm-rent. 
IV. The two i»rincipal armature windings are the ring and drum. 






1 . Fig. 4 1 is a 2-pole, 4-coil, ring, wind - 
ing around core of annealed soft iron 
wires or washers. Two circuits be- 
tween brushes. Nearly all cores, ring 
or drum, are now made from soft-iron 
sheet in washer shape. 



Fig. 43 is a 2-pole, 4-ccil, drum, lap 
winding over annealed sott-iron wash- 
ers starting from 1. Coil a b is firs< 
wound, then c (I, e f, g h in order. 
Back pitch, -•- 3; front pitch, — 2. 





43. 



Fig. 4:3 is a 2-pole, 8-coil, ring wind- 
ing. Arrows show direction ot cur- 
rents. 



Fig. 44 is a 2-pole, 8-coil, lap, drum 
winding. Back pitch, -( 7 ; front pitch, 
— 5. 



44 



HANDBOOK FOR ELECTRICIANS. 





Fig. 45 is a 4-pole, 20-coil, ring, four 
windings through arniatnre, making 
its resistance between poles = -j^ of 
that of the single winding. By con- 
necting each bar of the conimiitator 
with the one opposite, two brushes 
90'' apart will be sufficient. 

2. An armature winding is more readily followed by considering the wires, 
bars and poles rolled out upon a plane siirface as in fig. 47, for the armature 
shown in fig. 48. Or, uijon paper, draw rectangles to represent all poles, in a 
parallel row show all of the bars, and then draw single lines from the bars to 
represent the coils as they are found on the cylinder in one position. 



46. 

Fig. 46 is a 4-pole, 17-coil, wave, drntQ 
winding. Back pitch, 9 ; front pitch. 9. 
Two circuits between brushes. Short 
lines having arrowheads represent 
wires along the length of the cylinder ; 
outside wires are back connections, 
inside wires, front connections. 





48. Drum Wave Winding— 4=Pole. 



47. Drum Wave Roiled Out. 



The features of recent slow speed armatures are — 

(a) The core is composed of japanned washer- 
shaped discs stamped out of sheet iron and solidly 
assembled on a sjiider (fig. 52). Air ventilating 
ducts run radially and longitudinally throiigh the 
core, and deep slots in which the coils are to be laid 
run longitudinally along the cylinder surface. 

(5) The copper coils (figs. 51 and 53j are forged or 
formed on a collapsible block, then covered with tough 
and moisture-proof insiilation and laid in lap form 
(fig. 50), or in wave form (fig. 52) in the slots between 
the teeth of the cylinder core where they are so firmly 
wedged by fiber and bound by band wires that no part 
can vibrate. 

(c) Opposite active parts of the same coil occupy as 
nearly as possible corresponding positions (figs. 50 and 
52) under the poles. Ends of coils are mechanically 
fastened and soldered to their proper bars so that open 
circuit may not occur. Back and front wires are 
equal. The air space is everywhere the same and the 
pull of all field magnets, alike. This method of wiring 
requires a minimum of length and allows any injured 
One Lap Coii. coil to be easily replaced. 





49. W=e M. P. Generator Armature, with WindinK I'nfinished. 




50. (i. K. Core. Lap \\ indinK Hejcun. 



44 



THE DYNAMO. 



45 



(d) The bars of the commutator (fig. 54), of H. D. copper in.snlato(l by amber- 
colored mica, are siifiBcient in number to keep the P. D. between any t w< > adjacent, 
l)elo\v 10 volts. 

((') The bearings (fig. 55) are self -aligning, also self -oiling by means of revolv- 
ing rings on the .shaft. 




54. (ieneral Blectric Commutator. 



V. Field trindings. — There are five methods of exciting the magnet which 
in turn render magnetic the space or field in which the armature coils revolve: 
Permanent Magnets (fig. ('•()), Separately Excited (fig. 56), Series (fig. 57), Shunt 
(fig. 5fS), and Compound Winding (fig. 59). 




^ ^ ^ ^ 




57. 





58. 



46 



HANDBOOK FOR ELECTRICIANS. 



The series winding is regulated by varying the resistance of a coil in shnnt 
to it. The slmnt winding is regulated by varying the resistance of a coil in 
series with it. The comiiound winding uses both methods of regulation. 



(B) SPECIAL SERVICE GEIS^ERATORS. 



I. The telephone call box dynamo (fig. 60) has 
three permanent magnets M to create its field. 
The single Siemens armature coil C, of fine wire, 
has one end fastened to the soft-iron core at a and 
the other end to the insulated pin c. The alter- 
nating current generated passes out through e to 
a spring in contact with it and returns through 
frame and bearing to a. 






II. United States fuse-firing djmamo (fig. 61) 
is series wound, self -exciting. The Siemens 
armature coil is revolved eight times by means 
of its pinion gearing into the ratchet bar R when 
pushed down. At the end of the stroke the bar 
strikes and opens the short-circuiting key P and 
allows the fiill current to rush into the external 
circuit. No. 3 (16 by 8 by 5 inches) weighing 
18 pounds, has 0.05-inch wire in magnet (If ohms), 
and 0.032-inch wire in armature (0.9 ohms), 
develops 15 volts and will fire eight fuses in 
series. 

C= 15-- (2.7 + i?). 



/'■ 






vz::::::\ 


' 


/^ 






Y 

"n 


\K^. 


v: 


>/■ 


) 




Cl.. 


























jL 






3>cn 


\ .T>| rt 1 1 


w 


a- 




bnj 














1 






i 1 


\] rx"^ 








^x 






8 


r 



At/ 

Fuaes 

Yi 



\ 



61. Dynamo for Firing Fuses. Second View of Circuits. 

Ill — General Electric Direct-Coupled Generating Sets. 

1. Foundations — Installing. — The generating set (fig. 62) should be provided with 
a foundation of ample proportions and mass to absorb the vibrations produced 
by the reciprocating parts of the engine. When placed upon a good foundation, 
the set will give the best results, require the least amount of attention, the bear- 
ings will run perfectly cool with a small amount of oil, and, in general, operating 
expenses will be reduced to a minimum. 




63. Governor. 



47 



THE DYNAMO. 



47 



The engines should run without porceptiltle viVn-ation or noise if jiroperly 
installed and i,'iven a reasonable aniomit of attention. When a ^'ent'rating set 
is installed in a building for isolated light or power, care should bf taken to 
avoid having the engine foundation eonneeted in any way to the foundation 
of the building or its adjacent walls. Pipes leading to the engine should also 
be as free as possible from connection to walls. A wooden l)ase frame is some- 
times found de.sirable under the generating set when installed in a building, as 
it will, to a large extent, prevent the transmission of ntuse and vibration. 

2. Stcdin jiiju's, i)ressi(re and speed. — Sharp bends in the steam and exhaust 
pipes should l)e avoided as much as possible, and the steam pipe should be 
covered with good nonconducting material. A drain pipe with valve should 
lie provided just a])ove the throttle valve in order to drain the ]iii)e lino of con- 
densed water. A separator .should be installed on the steam pipe close to the 
engine, to i)rotect it from water that is occasionally carried over with the 
steam. Often considerable trouble is experienced \\\i\\ foaming boilers, and 




62. M. p. 6-20-305-125. Form of Ci. E. Generating Set, with Single 
1 1 by 8 inch Cylinder. 



acciilents are liable to hai>pen if no separator is Ti.sed. When the engines aremn 
noncondensing, a drain pijie i inch to i inch in diameter, depending upon the 
size of the engine, should be placed at the lowest point of the exhaust pipe. 

;{. The e)i(/i)ie. — ((i) The engine and generator are tested for several hours 
with the full rated output of the generator, and the engine is regulated to the 
proi)er speed, wliich is stam])ed on the name-plate. The valves of single engines 
are set to operate economically at a steam pressure of 80 pounds, and the ratings 
of single engines are based on*8() itounds steam pressure, noncondensing. Ver- 
tical tandem compound engines (tig. 7:]) are adjusted to operate at \2'> pounds 
steam pressure, conden.sing, or 140 pounds nonconilensing, and the sets are rated 
on this basis. Both single and compound engines give tlie be.st re.sults when 
oi)erated at their rated pressures, and if an engine is desired to run at a steam 
])ressure lower than standard, it may be necessary to adjust the governor (fig. 63) 
bv tightening the spring until the rated speed is obtained. Single engines may 
be run on a steam jtrt^ssure up to 100 pounds without difficulty, but for higher 
jiressures use rediicing valves. 



48 



HANDBOOK FOR ELECTRICIANS. 



(b) If the speed of the engine is unsteady, the cause is probably sticking of 
the valve or parts of the governor, or loose connections in the valve motion. 
The governor should be taken apart, bearings thoroughly cleaned, and the lubri- 
cant removed. Only the best quality of thin grease — mixed with cylinder oil if 
desired — should be used in the governor. 




64. Piston Rod and Crosshead. 




65. Governor Connecting Rod. 





66. Piston Valve— 20 KW. and Over. 




67. Piston Valve— Below 20 KW. 

(c) The governor (fig. G3) has few moving parts and minimum friction. As 
the load is decreased, the fly weight, by increased centrifugal force, is moved 
out and the eccentric pin (seen near the center hole of the fly wheel) is moved 
toward the center of the shaft. This reduces the throw of the valve, changes 
the steam admission and compression to suit the load, and preserves the engine 
speed within small limits. 

The governor can change the cut-off from f to 0, and the speed can be changed 
within certain limits by tightening or loosening the spring. It will not allow, 
with yO pounds steam, a A'ariation exceeding 2i per cent in the number of its 
revolutions for a change from full load to one-fifth of the same ; nor exceeding 
3i per cent for a change from 80 to 100 pounds pressure ; nor exceeding 5 per 
cent for both changes. 



THK DYNAMO. 



49 



(fl) The relief valves for takiiiK care of the water that enters the cj'liiuler 
should be adjusted ten* the working pressure at the engine, and should open freely 
at a pressure i) povuids greater. 

(e) If any valves leak, they should be taken out and cleaned, and the seats 
reground. The leak .should not be stopped by increasing tlie pressure on the 
valves. 

(/) The engine will run without noise, A-ibration or heating in any of its parts 
when given i)roper care and attention. All working surfaces are liberally pro- 
portioned, and wear is very .•flight, but as .soon as any loss motion appears, it 
.should be immediately taken up by the adjustment provided for that purpose. 
Use only Garlock square or other first-olass packing, and tho best quality of 
cvlindcr oil. 





68. Coiinter=C!ockwise Rotation. 69. Engine Side. 

•1. The (jeiwrator — (a) To plave iltc sjxjols. — Observer is suppcsed to be inside 
of frame and looking at faces of two lower pole pieces. Large arrow indicates 
direi'tion of rotation of lower half of armature. Small arrows corresi)ond to 
arrows on si)ool tianges, the spools being so placed that the arrows point in oppo- 
site directions on each succeeding si)Ool. Arrows on bearings must point in 
direction of rotation. 

(/*) To adjust the compounding. — Every compound generator is provided 
with a .shunt consisting of strips of (jerman silver witli suitable terminals 
attached, which should be eonnected to the .series fiekl terminals on the right- 
hand side facing the commutator (fig. 08). Any degree of compounding up to 




70. Freeing the Pigtail from the Brush Holder. 



50 



HANDBOOK FOR ELECTRICIANS. 



10 per cent may be obtained by changing the length of this shunt. The arma- 
ture and field coils are, during winding, subjected to an insulation test with a 
voltage many times higher than the normal and their resistance is watched to 
locate short or open circuits. 

(c) To set tlie hruslies, place the brush holder on the studs so that the boxes 
A (see fig. 70) which hold the brushes, shall be about i inch from the surface 
of the commutator, and clamp them firmly in this position. From time to 
time the brush holder should be turned slightly on the studs to compensate for 
the wear of the commutator. 

Place the brushes in the holders, as shown in fig. 71, and screw down the 
pressure spring B by turning the nut C, so as to give about 1^ pounds pressure 
for 1^-inch brushes and f pound for f-inch brushes. Nothing is gained by 
increasing the x>ressure per square inch on a carbon brush above 2 pounds, as 
the resistance per square inch beyond this point is practically not reduced, 
whereas, the friction is increased in direct proportion to the pressure. 

Fit the carbon brushes carefully to the commutator by passing beneath them 
No. sandpaper, the rough side against the biiish and the smooth side held 
down closely against the surface of tlie commutator. Move the sandpaper in 
the direction of rotation of the armature, and on drawing it back for the next 




71. Correct Position of Brushes in Brush Holder. 

cut, raise the brush so as to free it from the sandpaper, then lower the brush 
and repeat the operation until a perfect fit is obtained. If the brush requires 
considerable sandpapering, No. 2 sandpaper may be used at first, but the final 
fitting must be done with No. 0. If an attempt be made to fit the brushes 
without raising them when drawing the sandpaper back, it will in every case 
fail to give satisfactory resiilts. When thick bru.shes are used— say f-inch— in 
addition to following the above instructions, the machine should be run as long 
as convenient without load in order to improve their surface. As soon as the 
brushes of a set appear to make a good fit one of them should be removed from 
the brush holders in the following manner, to determine if they are worn to a 
surface : 

Unscrew the stud D, thereby freeing the end of the pigtail E, and push the 
spring B forward so that there will be plenty of room to draw the tip E on the 
end of the pigtail through the slot F (see fig. 70). Then draw the pigtail 
through the slot F, bend it forward and turn the spring B to one side as shown 
in fig. 72. The brush may then be withdrawn from the box. In replacing the 
brush these directions should be followed in reverse order. 

Care should be taken not to disturb the nut C after it has once been set, as it 
is not necessary to alter the pressure of the spring B in removing or replacing a 
brush. By this means a practically constant pressiire may be kept on the brush. 

(d) To adjust the brush yoke.— The design of these machines is such that no 
movement of the brushes is necessary when load is thrown off or on. The 
brushes should be set at no load, so that the reference mark on the pedestal is 
in line with the reference mark on the brush-holder yoke. With the brushes in 
this position generators will compound according to the name-plate stamping. 

(e) To take care of commutator.— The commutator, brushes and brush holders 
should at all times be kept perfectly clean and free from carbon or other 




73. Small Direct Coupled M. P. 6 25 450, with Vertical Tandem 
Compound Knjfine. 



THE DYNAMO. 



51 



dust. Wipe the commutator from time to time with a piece of canvas, lifjhtly 
coated with vaseline. - If vaseline is not at hand, use oil, but lubricant of any- 
kind shouM be ai)plietl very sparingly. 

If a connnutator wlien set up begins to give trouble bj' roughness with 
attendant sparking and excessive heating, it is necessary to immediately take 
measures to smooth the surface. Any delay will aggravate the trouble and 
eventually cause high temperatures, throwing of solder and possil)ly displace- 
ment of the segments. No. sandpaper fitted to a segment of wood with a 
radius equal to that of the commutator, if ai)plied in time to the surface when 
running at full speed (and if possible, with brushes raised), and kept moving 
laterally back and forth on the commutator, will usually remedy the fault. If 
this does not suthce, it will then l)e necessary to tighten up the segments and 
turn them off true. A machine tool will not leave the surface smootli cTiough 
to give perfectly satisfactory results. It is always necessary before i)utting on 
the load after the conmiutator has been turned, to carefully smooth the surface 
Avith the finest sandjjaper, thus removing all traces of the tool point. 




72. The Brush Ready for Removal. 



5. Startiiif/ (nid rnnniny tlic set. — {a) Before starting, see that all screws and 
nuts are tight, that the oil cups are filled with oil free from dirt and grit, 
and that all working parts are well oiled. The feed should then be adjusted to 
give the recittired amount of oil to each bearing. The waste oil collects in the 
base and may be used again after runiiing through a filter with some new oil 
added, but no advantage results from using too mucli oil. Turn the ai'mature 
by hand to see that it is free and does not rub or bind at any i)oint. The drain 
valves on the cylinder .should all be opened to allow the conden.sed water to 
escape. Turn the steam on slowly at first, allowing the_ cylinder to get well 
warmed up and giving the condensed water a chance to ge't out before turning 
on full steam pressure. The piston valve will heat up as soon as the steam 
enters, but the cylinder reciuires some time before it expands sufficiently to 
allow the valve to move freely. When the engine has started, see that the oil 
rings in the l)earings are in motion. 

(/>) As soon as the machine is set nuniing s e that it excites itself to full volt- 
age. If it does not, trace ont tlie field connections and test tlie polarity. 

Wlien the machine is to run in parallel with others and its polarity is wrong, 
raise the brushes and excite the fields by closing the main switch from the 
l>us bars. 

(c) A continuous run of four hours on full load shotald not rai.se the tempera- 
ture of an armature or field coil 60 F., or of the commutator 72° F., above the 
air as determined by placing the bulb of a thermometer surrounded l)y waste 
upon it after the machine is stopped. Directly following the above, the machine 
will sustain a heat run continuously of two hours on 33 per cent above its full 
rated load without injury to the engine or dyiiamo. After this run which 
should only be done by an experienced i)erson, it is a good time to make the 
in.snlation tests and to look for meclianical defects. 

((/) To remove the armature, unbolt and lift off the upper field half, take off 
the brush holders, brush yoke, pulley and bearing caps, and put a sling on the 
armature. 



52 HANDBOOK FOR ELECTRICIANS. 

(C) DISEASES OF DYNAMOS. 

The DISEASES are stated in small capitals, their causes in italics ; the remedy 
follows the cause when it is not evident and not structural. Dr. F. B. Crocker 
gives the following systematic statement : 

I. — Sparking at the Commutator is caused by: 

1. Armature carrying too much current. — Dtie to overload, loose connections, 
reversed polarity, excessive voltage of current, short circuit or grounds in 
dynamo or external circuit. 

2. BrusJies not at ttte neutral points. — Shift the rocker to a point midway of 
those which give sparking. 

3. Commutator rough. — Apply No. sandpaper (not emery) laid inside a 
wooden form to fit the commutator, and before replacing brushes take care to 
remove all traces of sand or copper dust. 

4. Commutator very rough or eccentric or having a flat bar. — Turn the commu- 
tator down, revolving slowly in its place witiiout piay, by means of a sharp- 
X)ointed tool, and finish in turn with a smooth flat file and emery ; preferably put 
armature in a lathe. A flat is often caused by an open coil. 

5. A high 6«r. — Tap it down and tighten up the clamping ring, or, if it can 
not be done, file the bar down. 

6. Brushes making bad contact. — Due to roughened or burned ends, improper 
bedding, to oil, carbon, dust, or to insufficient pressure. 

7. A short or broken circuit in armature or field ; a reversed coil. 

8. A ground in the armature.— Liocate and replace the coil. 

9. A toeak field or excessive shunt field resistance. 

10. Unequal poles due to armature reaction being relatively too great. 

11. Too high brush resistance, as with certain carbons. 

12. Vibration, from unbalanced armature or pulley or faulty belt. 

13. Chatter of carbon brushes.-~C\ea.n commutator and apply vaseline or oil. 

14. Surging current, from uncertain engine governor action. 

15. Break in armature, only while running due to centrifugal force. 

II. — Heating of Commutator and Brushes is caused by : 

1. Heat from adjoining bearing or from armature. 

2. Sparking. 

3. Black carbon film from the brushes, which offers resistance. 

4. Bad connections in brush holder. 

5. Arcing between bars or other parts of the commutator. 

6. Heating of carbon brushes from current. — Coat the carbons with copper 
deposit. 

III. — Heating of Armature or Field Magnet is caused by: 

1. Excessive current. — Same as cause 1 of sparking. 

2. Coils short-circuited permanently, or due to contact in armature only while 
running. 

3. Moisture. — Showing vapor driven off after a short run. Bake in an oven or 
send fiill current until vapor. ceases. 

4. Foucatdt currents in iron core or Eddy currents in the coils, structural. 

5. Reversed coils. — Send a current through armature or field and note the 
deflections of a compass needle all the way around. 

6. Heat from adjacent parts. 

IV. — Heating of Bearings is caused by: 

1. Lack of good mineral oil. 

2. Grit or dirt. 

3. Shaft bearing rough or cut. 

4. Bearings too tight. 

5. Shaft sprung, so that it tarns harder at one point of a revolution. 

6. Bearings out of line or proportion. 

7. Side thrust of shaft against bearings. 

8. Too tight belt. 

9. Armature closer to one pole than to another. 

10. Heat from adjacent part. 

V. — Abnormal Noise is caused by: 

1. Armature or pulley out of balance. Bad foundations. 

2. Armatm^e striking a pole piece; rebabbitting, new liners, or reducing the 
projecting part. 



THE DYNAMO. 53 

3. Side thrust of shaft due to bad alignment. 

4. RattliiKj of loosr scrcu's or otlwr jxirt.^i. 

5. Hiiiiniihig or s(jneahin<j of hrKshes. —hift one of a set off at a time and, 
when found, aijply a drop or two of oil. 

6. Flapj)iii(j or slij>j)iti<j of belt, or striki)ig of a hell joint on tlic jjiiUcjjs. — 
Tigliten or loosen the belt : never apply resin. 

7. Hninininij of ariiKitiirc tectli jxissiny tlic edge of jiole jiieees. 

8. Straining of coupling in direct connected sets. Reline and readjust. 

VI. — Speed too Low is caused by : 

1. Overload. 

2. Short circuit in armature. 

3. Armature ntriking pnh' pieces. 

4. Shaft not free to revolve. 

5. Engine too slow or slipping belts. 

VII. — Failure to Ge.\er.\te is caused by: 

1. Hesidnal magnetism too urak, due to (a) vibration, (b) proximity of another 
dynamo, (<•) earth's ma,<,'netism, (d) accidental reversed current throui^h field 
coils, but not siHJieient to reverse the magnetism. Send a current from a few cells 
through the field coils in the jiroper direction. 

2. JRever.'^ed coiniections. or direction of rotation. 

3. Short circuit to a shunt di/namo. 

4. Field coils i>pposed. A compass needle will show. 

5. Oi)en circuit in dynamo, at a brush contact, switch or fuse, or in the exter- 
nal circuit to a .series machine. 

6. Jirushes not in proper position. 

VIII, —Variation op Voltage is caused by : 

1. Irregular speed. 

2. Lap or other bad belt Joints. 

3. Short or open circuits in armature or field. 

4. Incorrect eonnectiorts. 

5. Engine governor out of order. 

(I)) tup: CAKK AXl) MAXACiKMEXT OF T). (\ DYXAMOS. 

It is assumed that the machinery is ])roperly constructed and installed. The 
engineer on taking charge and subsecjuently at intervals makes an — 

1. l)i.spection and adjustment. — Every part of an electric plant is kept scrupu- 
loiisly clean if well managed. 

The caps of bearings are taken off; all dirt, grit and old oil are removed; oil 
passages are cleared ; the journals are examined ; the caps are screwed back with- 
out binding; the l)oxes are lilled with the best mineral oil. 

The armature, rotated ))y hand, is examined for injured insulation, a Imlge, 
loose coil or binding Avire, ccjntact with pole piece, unecpial distance between 
armature and pole i)ieces due to wear or bent axle, contact between lug, tendency 
to stop in the same place. 

A good commutator is cylindrical, .smooth, and clean, and has a dark-brown 
polished appearance. A high bar must be tiled down. For a low bar or fiat, 
the whole commutator must be turned down. A rough surface from excessive 
sparking can be smoothed by fine sandpaper (not emery) laid inside a wooden 
form cut out to fit the cylinder which, after the brushes are raised, is given a 
slow speed; liefore letting down the brushes, make sure tliat no metal dust or 
filings lie in the insulation between the bars. If the commutator has worn 
eccentric or in ruts, it must be turned down by a tool on a sliding rest fastened 
to the bed. 

The brushes, copper or carbon, with ends alike beveled and evenly bedded on 
the connnutator, should .set with tips exactly 180 degrees i\\y,\v\ in ~'-i)oie machines, 
90 degrees in 4-pole, etc., in i)erf'ect alignment and at e(iual lengths from each 
rocker arm along which the bruslies are, as a rule, tinevenly spaced so that the 
wear on the whole commutator will be as nearly uniform as possible. In the 
absence of .setting marks, adjust the tips of one set of brushes carefully to the 
edge of a bar and count the liars for the exact jiosition of the other set. ' 

The brush sjirings are Jiext adjusted to a uniform, light, yet reliable, contact 
sufficient to take the full current without sparking. Too "great iire.ssui'e will 
soon wear and heat the commutator and cause sparking ; too light pressure will 



54 



HANDBOOK FOR ELECTRICIANS. 



cause vibration, sparking and heating. Pressure of carbons seldom exceed 1 
pound per square inch of contact siirface and is usually less ; of copper brushes, 
is much less. 

See that the rocker can with steady force be moved over its range, can be locked 
in any position, and that no side play of it disturbs the bedding of the brushes. 

Oil, water, grit or dust on any conductor insulation or part of the machine, 
a wrong or a bad connection, an unsoldered joint, a loose niit or bolt, or a tin 
oil can, tool, or loose iron near the machine will be quickly detected by a capable 
engineer and removed. 

Dynamos usually run counter clockwise to a person at the commutator end. 
To reverse the rotation, shift the positive brush with its connections to the posi- 
tion of the negative, likewise shifted. To reverse the current, exchange the 
leads or reverse the polarity. 

A belt should be heavy, single, or link, +-inch narrower than pulley, without 
lace or lap, and just tight enough to prevent slipping. The pull is always on 
the lower run. It remains on the pulleys in intervals between daily runs of the 
dynamo slid back 6 inches. 

N and S are labeled or marked by the engineer on magnets ; + and — , on 
terminals; "on "and "off," on rheostats; initial letters of connections, on volt- 
meter switch points ; currents on feeders, etc. , for his aid in case of trouble. 

The inspection extends also to a run of the plant. 

STARTING. 

2. See that all parts, screws, and nuts are tight; turn the armature by hand 
to see that it is free and does not rub or bind ; put on the belt, tightening 
gradually after starting. Note that the main switch to line is open for shunt 
or compound machines and closed for a series ; that the field rheostat is open 
and the V. switch is turned to dynamo + and — ; fill oil reservoirs and start 
lubricators if sight feed; start the machine very slowly, noting that the oil 
rings turn and belt runs smoothly ; bring it gradually to full speed ; drop the 
brushes down if not there permanently ; close field rheostat and cut out resist- 
ance for a gradual rise of potential, as shown by the voltmeter or pilot lamp, 
to the proper limit ; stand ready to stop if anything goes wrong ; shift the brushes 
at the first sign of sparking. 

To light lamps raise the dynamo to its voltage and close in order and deliber- 
ately the overload, main, and feeder switches, watching the ammeters whose 
deflections should be anticipated. Of the feeders, close smaller first, if there is 
a choice, to increase the load as steadily as possible. 

Before closing a feeder on a storage battery, find the battery's voltage and 
make sure that the voltage of the dynamo is 5 to 10 volts greater, while at the 
same time the lamps are kept at their normal voltage by the heavy current 
regulator. 

A new or a repaired machine is first run empty, or on light load several hours 
with slack belt and plenty of oil. 

If two compoimd machines are in parallel (fig. 75), start and close one on the 
main circuit as above ; bring the other to normal speed ; close its field rheostat 



Switch or Rheostat 




to excite its shunt field ; next close equalizing switch and regulate with shunt 
field rheostat to the potential of the first machine; then close main switch. 
Ammeters will show if either is doing its share of the work. To stop, reverse 
the above steps. 



THE DYNAMO. 55 

RUNNING. 

3. A dynamo properly started .and siibseiiuently watched requires little care. 

Any trouljle should be detected at its bcj^inninj,' and corrected, if possible, 
vnthont stopping. Sparking is the worst tronble. Allow no unusual or 
unnecessary noise to continue, nor change of voltage or speed, nor abnormal 
heating of bearings, field coil, armature or commutator. The heating of any 
part wliich the liand can bear indefinitely witliout di.scomfort is .'^afe. The 
limit in modern dynamos and mot(n-s is 80 F. of any part above th(» room ; if 
greater than this, something is wrong. 

Feel the air near the armature revolving. The commutator should not be 
more than 10 degrees warmer than the armature. 

Overloading is the cause of most trouldes. 

Handle a conductor with a stick or insulated tool. Use one hand only around 
a dynamo. Wear rubber gloves and .shoes for r)00 volts or more. 

Stop the djTiamo if violent armature sparking can not be suppressed or smok- 
ing appears. 

In good dynamos the "lead" is small and the rocker has a wide range with- 
out sparking. Its ])roper position is midway of the two jioints which shows the 
first sparking or at that point which gives the highest voltage. Leave the 
rocker always clamped. 

The lead of dynamo brushes advances slightly with rotation as the loa<l 
increa.ses. 

One of two or more brushes in a set may be removed and cleaned while run- 
ning. If carbon brushes "chatter," clean the commutator. 

The oil t)n a new or repaired djniamo is dra^^^l off after each run for three or 
four days to get rid of the grit. Afterwards draw off and add a little fresh oil 
every three or four weeks. 

In case of a hot box, do not shut down unless the following alternatives have 
failed: Slacken the belt, loosen the cap, put more oil on, lubricate with vase- 
line or cylinder oil. If the heating is reduced, polish the shaft with crocus 
cloth and scrape the boxes after shutting down. But if the heating continiies 
to increase take off" the load, slow down, loosen caps, get the belt off as soon as 
possible, keep the armature movin.g to i)revent sticking, take off the caps, then 
stop the revolving, take out the linings and allow them to cool in the air. Do 
not throw them into water. Scraping the linings can (mly be done by an 
experienced i)erson. The shaft is also polished with crocus. Do not use ice or 
water to cool a hot box. 

Oc^'asionally hold a small piece of clean white cotton cloth — never waste — on 
the commutator to A\ipe it clean: then put on two or three drops of vaseline. 

Keep printed directions and diagrams of all circuits posted. 



4. If the djniamo is alone and not charging a battery or supplying a motor, 
slowdown the engine to a few revolutions; oi)en main switcii ; raise lirushes 
if copper ; hold clean white cloth on commiitator until no dirt shows : stop the 
engine: open the feeders and field rheostat; feel the armature wanding for heat; 
loose the l)elt. 

If a battery is being charged, reduce the charging current to a few amperes 
and open the battery switch, tlien slow down the engine and proceed as above. 
If a motor is being supplied, it must first be gradually cut out by its rheostat. 

If the dynamo is working in parallel, reduce its current to nearly and open 
its switcli before reducing speed. 

To prevent mechanical shock, never open a main switch carrying more than 
a few amperes excei)t in case of emergency. 

After stopping, dust the dynamo and clean it thoroughly while warm with 
cotton cloth — never waste. Remove any trace of oil or metallic dust, esi)ecially 
from bnish, brush holder, or commutator. Every part is kept scrupulously 
clean. A bad joint or a loose nut is detected. Cover the machine. The room is 
then swept and diisted and, if not suulighted, a lamp is maintained to keep it dry. 



-THE SWITCHBOARD. 



(A) ARRAINGEMENT AND CONNECTIONS. 

1. The switchboard is the electrical center of an installation. Its distributing, 
measuring, regulating and protecting apparatus are systematically and con- 
veniently arranged on the front of one or more slate panels held in a metal 
frame. On the back the bus bars and all copper wires connecting the apparatus 
are accessible, insulated, rigid and straight between supports except where they 
are bent out 1 inch in crossing 

Wires running from the switchboard are neatly aligned and run horizontally 
or vertically along ceiling and walls in conduit or taut between large porcelain 
insulators on asphalted strips. Connections are sweated and bolted ; small wires 
may be jointed and soldered. As a rule, the drop from a dynamo post to any 
feeder on the same leg is less than one-foiirth of 1 per cent. Fig. 78 suggests 
the entire system where cells are charged and discharged in series. 

2. The switchboard connections should permit four conditions — first, the 
dynamo, or dynamos in parallel, to feed directly all lamps, motors, searchlights, 
etc., or any part of them, and in large installations to leave one spare unit idle; 
second, to charge the battery or batteries alone ; third, to do both simultane- 
ously ; fourth, the battery to supply in case of a breakdown to the machinery, 
all current to the circuits of its emplacements except motors and searchlights. 

3. There will then be one generator panel or board of panels in the power 
room centrally located, and a panel for each battery reserve near its emplace- 
ment, but not in the same room with the battery. If there is only one battery 
and the dynamo is near it, the two panels will be mounted together in the 
dynamo room. 

The panel is of best slate, li inches thick, held vertically 2 feet from the wall, 
1 foot from floor by a metal frame from which it is insiilated by ebonite bush- 
ings and washers. The dynamo i)ane], about 6| by 2f feet, wnll, when 
necessary, be nrounted with others like it in a continuous board. The battery 
switchboard is about iii by 3^ feet wide and its bus bars will receive their supply 
either from a dynamo feeder or battery. A searchlight must have its own 
switchboard, supplied by a feeder from the dynamo board's bus bars. 

4. The simplest and best form of switchboard arrangement affording, with the 
least apparatus, ample control and protection for one or any number of emplace- 
ments and batteries, is given for both generator and battery panel fronts on 
page 74. It will no doubt be adopted in the course of a few years. For a single, 
compact i)lant the arrangement may be as on page 75. 

On account of the diversity of switchboards which will be met with, several 
diagrams are given below. 

(B) GENERAL DESIGN. 

The general design and apparatus ought to allow : 

Separate feeders from dynamo board to battery panels, motors and search- 
lights ; from each battery panel to its centers of distribution. 

Such regulations that all centers of distribiition may be kept at the same poten- 
tial, all batteries may have their normal charging and* discharging currents, and 
the charging of two battery halves may be equalized. 

Magnetic protection to every dynamo, motor, and battery against overload and 
underload. 

Measurements of C and V of any part desired and of leakage. 

The details of apparatus are given in figs. 79 and 80. The same apparatus is 
indicated by symbols for other boards. The best switchboard arrangement 
to be found in forts appears on pages 58, 59. 

1. Weston voltmeters, V, reading to 150 ; a recording volt gauge for the battery 
is advisable. 

2. Weston shunt ammeters, A, reading to one-half excess of the maximum 
current. 

(56) 




78. W=e Switch Board Front. 



66 



THE SWITCHBOARD. 57 

3. 6-point voltmeter switch on battery panel connected to give at will the 
voltage (a) between bns bars, (6) of first half battery, (c) of second half battery, 
(f/)of whole battery, (c) V)etween -• bar and ground, (/') between — ])ar and ground ; 
4-point switch on dynamo panel to give the voltage (a) between supply mains, 
(6) bus bars, (e, (/) either bus and ground. 

4. Main regulating rheostat M R of noncombustible, nonabsorptive material is 
necessary to reduce the bus bar voltage while charging the ])attery. It has range 
and capacity to carry indefinitely witli less than 200 F. rise, the charging cur- 
rent of both battery halves within 5 i)er cent of the normal while the l)us bars 
remain at 112 volts; enough stops are jn'ovided to keep the bus bars within 1 volt 
of the potential necessary to snpjdy the lamps. 

5. Equalizing rheostats, E It, E R , have each ten steps for a total drop of 10 
volts, and in construction are like the above. 

6. The field rheostat, F R, supplied with the dynamo, can lower its maximum 
voltage on load to 110. 

7. All rheostats are required to have: 

Capacity to carry its ma :imum current indefinitely with less than 200^ F. rise, 
and 30 per cent overload for one minute. 

Contact arm on a spindle and toucliing one point before it leaves the other. 

All material fire and moisture jiroof and conductor nonoxidizable. 

Comi)actness, ventilation, and abundant radiating surface. 

Insulation of 1 megohm between conductor and frame under A. C. test. 

"Words "high," "low," or "raise," "lower," to indicate the turn of contact 
arm to change the voltage. 

8. Its overload circuit breakers, O L, oi)erate with certainty and excess of force 
within 5 per cent of adjustment. This is usually made to open automatically 
the circuit at one-fourth increase of the normal current. 

9. Its underload C. B's. operate within 5 per cent of adjustment, and is usually 
set to open the circuit with a fall of o or 10 amperes if the C. B. is "no current," 
and of voltage 30 per cent if the underload is "low voltage." It should not 
catch if the current or voltage is lower than that of the adjustment. Both O L 
and U L circuit breakers have carbon protection to the main contacts, and if 
combined on one base, have but one trip-catch. 

10. Fuses have copper tips stamped with 80 per cent of the amperes which 
they can carry indefinitely, and will therefore blow at one-fourth excess of their 
normal current. 

11. Knife switches are 50 amperes or larger, double pole, single or double 
throw, (piick l)reak, fused, carbon -tipped, hinged, nnd so constructed that con- 
tact will occur along the entire edge of the jaw at the same time, and no current 
can pass throiagh a hinge or spring. Single-throw are closed by an upward 
motion to avoid accidental closing. 

12. All conducting parts of the switch board are of drawn copper and have a 
cross section of about 1 square inch per 400 amperes; all joints are sweated and 
bolted with a contact area of 1 square inch per 180 amperes ; all sliding contact 
surfaces have 1 square inch per 40 amperes. Bearing parts are phosphor-bronze 
or brass. 

(C) THE U. S. ENGI1ST5ER SAVITCHBOARD. 

1. Figs. 79 and 80 give the details of apparatus and wiring of the djniamo 

and battery panels. The feeders, h to the latter, come from FS off the 

dynamo panel's bus bars. 

Fig. 81 shows the connections on the battery svritchboard panel (fig. 80), while 
the storage battery is being charged, and fig. 82 while being discharged. The 
three figures are lettered to correspond. 

2. By this arrangement, tlu- l)attery of 58 cells is charged, 29 in series and 2 in 
parallel, by the throw of the triple-jtole d(Hible-throw switch, T J' D T, on the 
battery panel to the right and is discharged, 58 in series, liy its throw to tlie left. 
The plan allows other and distant batteries, each with its'own switch board, to 
be supplied by feeders from the same dynamo board's l)us bars, permits the 
d>niaino to feed all lamps, etc., at the same potential, offers little chance for 
mistakes or accident and fulfills the four conditions imposed in par. (A) 2, for 
isolated p. C. plants with battery reserves. But the apparatus is extensive and 
current is lost in dead resistance while charging and lighting at the same time. 

3. Details of the apparatus: 

(rt) In the Weston voltmeter T' (fig. 79) a pivoted coil, of which only three 
turns are shown in cross section, is held in position between the i)oles A' and 5 of 
a strong steel magnet by a light spiral watch spring F, seen in front, and one, R, 



58 



HANDBOOK FOR ELECTRICIANS. 



4 




t ;,. 

79. Present Generator Panel Apparatus in Detail. 



THE SWITCHBOARD. 



59 




5'B' 11 t.lU 

-•I'I'I'I'I'H 



T>-r^H 



u 



Si> TPDT 
—o TPDT 
I o 



Ai' 



5B ?.9 t.Ui 

I'hl'l'l'h 



80. Engineer Battery Panel. 



60 



HANDBOOK FOR ELECTRICIANS. 



like it, in rear, but drawn on the left in order to be seen. When a current passes 
through the coil, it revolves on its pivots on the same principle as the armatme 
of a motor and carrying with it the pointer along the scale. The V coil has 
many turns of very fine wire and a large fixed resistance in series, which is kept 
in the instrument case. 





TPDT 



81 and 82. Diagrammatic Sketch of Engineer Switchboard Battery Panel. 



(h) The Weston ammeter A is similarly constructed, but has fewer turns of 
coarser wire in the coil, which carries a very small but a fixed fraction of the main 
current through the shunt ^ ^ of German-silver strips in the main circuit. 
Ammeters and voltmeters are inclosed in iron cases to shield their fields, and 
they shoiild be handled with care, so as not to disturb the pivots or weaken the 
magnets. 

(c) The voltmeter switch F ^S has two brass arcs which are the terminals of 
the F circuit; also (fig. 79), four double brass points connected as shown. The 




83, G. E., D. P. Overload Toggle-Joint C, B. 



THE SWITCHBOARD. 



61 




brass ends of the lever (not shown) are insulated from each other and bear upon 
the arcs and two opposite points at the same time. The voltmeter can thus be 
switched in between (1 1 dynamo posts, {2) bus bars, (3) — bus bar and ground, 
or (4) + bus bar and j^round. The V S 
on dynamo i)anel has six points. 

{(I) In the overload switch O L the' 
knife edge kept open by a spring is, 
when pushed into the jaws by its han- 
dle (thus closing the circuit), held in 
that position by a trigger catch. Be- 
neath the catch and on the other side of 
its pivot is a plunger A* over a vertical 
soft-iron movable core I (fig. 84), sur- 
rounded at its iipper end by a coil car- 
rying the main current. When the 
current becomes too great the core is 
di'awn lip, strikes the plunger and catch 
and releases the knife. The spring over- 
comes the friction of the jaw on the 
knife whii-h then ojjens the circuit far 
more quickly anil surely than is done by 
a fuse wire. Tlie hand-screw shown 
below /, which moves the core up or 
down, affords regulation. 

The figure (X')) gives back connections 
of Ite C. B. and protected terminal f u.se. 

(e) O L and U L (fig. 79) is a combina- 
tion overload and underload automatic 
circuit breaker. In addition to the over- 
load cut-out, described above, there is a 
straight horizontal magnet with end 
pole pieces. It may be wound with fine 
wire connected for a fall in voltage as 
represented in the diagram, or with 
coarse wire in series with the O L coil 
to open for a fall in current. The arma- 
ture is a horizontal soft-iron ci'oss piece at the upper extremity of a vertical lever 
pivoted below and held by a spring noi-mally away from the magnet. When 




I^Ij3 



84. Ite Automatic Cut-out or Circuit Breaker. 




Diagram No. 1. 



Diugram No. 2. 



85. 



the knife of the switch is closed by the handle, the armatTire is automatically 
moved into approximate contact with the pole pieces and held by their maguet- 
isni. If tlie v()ltag(> falls to tlie adjustment, the armature lever is released and 
strikes the trigger catch, releases the knife and opens the main circuit. 



62 



HANDBOOK FOR ELECTRICIANS. 



(D) THE PREBIjE SAVITCHBOARD 

(Fig. 86), for a single plant with a battery reserve, requires little apparatus, 
loses very little energy in regulation, gives little chance for accident, and it is 
simple. Lamps are 110 volt; dynamo, 110 to 150 volts; 58 cells charged and dis- 
charged in series vary from 110 to 145 volts. 1. Dynamo to light lamps — close 
O L, MS, and i^^Sonly; MR is cut out. 2. Dynamo to charge battery — close 
T P D Tto right, O L, O' L', U L, and 31 S only. 3. Dynamo to do both— same 
as last and close F S. 4. Battery to light lamps— close O' L', T P D Tto left 
and F S. 




86. Preble Switchboard. 



(E) KEY WEST SWITCHBOARD. 

The relative sizes of wires, fuses, switches, etc., and the divided bus bars are 
sho\^^l in fig. 87. A shunt switch on the dynamo to the series field may be opened 
to raise the voltage. 

The ten end cells, active or nonactive, may be gradually added or subtracted 
from the main battery, as required, by an end cell switch. Its arm consists of 
two parallel brass bars sliding on the stops and on two different brass rings con- 
nected by German-silver resistance. By this device the battery circuit is never 
opened and no cell can be short-circuited 



fir i |ng b.b 



IStfi 



O 



\o\ 



W 



O.L. 



ISO ICO 



^•? f"? ?"? . ?'-? ?"? 

LIGHT B.B. J |2.UK J1pOW£r|b.B 

i\ TT 




87. Key West Switchboard. 



THE SWITCHBOAKl). 



63 



(F) THE c;oIjI>kn gate board. 

Tlie Goldon Ciatf> board (fig. 88) distrihutes current to three points, 1,500 and 
2.000 feet apart, eaeh having its own battery for a reserve. The generator and 
No. 2 stations are together. Battery and himpscan be .supplied sinuiltaneously, 
but not battery and motors. 

r- 




88. Qolden Gate Switchboard. 

(G) SAVnTClIBOARD ARRANGEMENT. 

The switchboard arrangement in fig. 89 for dynamo, single ])attery, with 15 
end active cells and 100 lamps, is economical. It fialfills the four conditions and 
the djaiamo and battery can b(» placed in parallel to supply 400 lamps for three 
hours. 




89. Shunt Dynamo, 45 Cells and 15 Active EZnd Cells. 



64 HANDBOOK FOR ELECTRICIANS. 

(H) TO OPERATE. 

1. No one should be allowed to touch the switchboard unless he is famibar 
with all circuits connected with it, the strength of main and feeder circuits, 
the insiilation of each part. Records of these are kept. 

2. Always close a switch deliberately and firmly, while watching the ammeter 
and voltmeter, whose deflections were previously known, and while standing 
ready to open. Main switches loaded are opened only in an emergency. 

3. The rule is to close feeder switches when practicable, so as to change the 
load as gradually as possible— the smaller first. 

4. Guard against dust or wet, overheating in any part, unsoldered joints, 
loose nuts, wires or other parts, bad contact of rheostat arm on any stop, instru- 
ment not holding its zero, switch twisted or dirtied so as to not make good con- 
tacts; apparatiTS out of adjustment. 

5. Leave all switches and circuit breakers open after a run. 




90. As Shipped and Prepared for Mounting. 



VI.— STORAGE BATTERY (CHLORIDE). 



(A) UNPACKING, SETTING UP, AND INITIAT^ CHARGING. 



1. Great care should be taken in impackiiij^ ami all su]).seqnent handling. 

2. Open boxes and crates on the "np"side. Lift contents ont, verify their 
number and condition, and never slide them by turning box on its side. 

•i. The construction of the stand is shown in fig. 91. Dimensions change 
^\^th size of jar. When jars are 15 inches high by 18 inches wide by 11 
Inches deep, the cross section of the timbers are 5| inches dee]) by 3j inches 
wide. When each shelf carries two rows of cells, there will be four longitudinal 
stringers to each shelf instead of two stringers, as shown for the single row 
of cells. 

4. The battery room should be so located or arranged that the temperature 
will bo moderate and the air dry. If the room is damp there is danger of leak- 
age from grounds and solution running over from absorption. 

5. Usually, natural ventilation is sufficient if the proper inlets and outlets 
for the air have been provided, but in some cases forced draft is necessary. To 
obtain the best results and life from the battery, the temperature should be 




91. Method of Mounting. Working Plan of Frame. 



GlaHs jitr. 
Wood tniy. 
Glasj insulator. 
Stringer. 
Iron liolt. 
t'rosspiece. 



(i 


Wimd ilowfl iiiii. 


h 


Negative idato. 


11 


r..st. 


SI 


]{uhlpcr ritiK f.pparafor. 


1 


l.cinl-roviTod Iiolt connector. 


N 


Vitrilicd Inick. 


.1 


Lead stn\p lug. 


O 


Lead terminal lu>;. 


K 


Positivr idat.'. 


I' 


Cojiper conn(•ctin^r comlucfor 



between 50" and 80" F. If the room is excessively hot (over 80) for any great 
length of time, the life of the plates is very ctmsiderably shortened. If the 
temperature is low, no harm results, but the available capacity is reduced. 

(). Place the jars, after tliey have been cleaned, in position on the .stands 
wliich should be .so situated in the room that each cell will ])e easily accessible. 
If the floor space is available, it is often preferable to install tlie cells on one 
tier, in which case a set of stringers properly fastened together and the 
insulating bricks will be all that is required. 

7. Place the elements as they come from the packing cases (see fig. 90) on 
a convenient stand or table (the elements are packed positive and negative 
together, the positive having i)lates of a brownish color, the negative of a light 
17H-5 (65) 



66 HANDBOOK FOR ELECTRICIANS. 

gray; the negative always has one more plate than the positive), cut the strings 
that bind them together and carefully pull the positive and negative groups 
apart, throwing the packing aside. After carefully looking over both elements, 
to see that they are free from dirt and other foreign matter, place two hard 
rubber separators on each positive plate, about an inch from and parallel with 
each vertical edge, and then slip these platens into position between the nega- 
tives, which have been placed crosswise on a board about two-thirds the width 
of the plates, so as to allow of easy readjustment of the separators, which may 
become disarranged (fig. 91). 

8. To facilitate the lifting of the elements into the jars and to prevent the 
disarrangement of the separators when doing this, a short strip of webbing 
should be used; lay this on the board under the element (fig. 90). When 
putting into the jars, be careful that the direction of the lugs is relatively the 
same in each case, thus causing a positive lug of one cell to always connect 
with a negative of the adjoining one and vice versa. This insures the proper 
polarity throughout the battery, bringing a positive lug at one free end and a 
negative at the other. 

9. Just before bolting or clamping the lugs together, they should be well 
scraped at the points of contact, to insure good conductivity and low resistance 
of the circuit; this should be done before the elements are taken apart and 
dii-ectly after unpacking, if the battery is to be set up at once. The jars rest on 
sand in wooden trays on glass insulators standing on framework as shown 
above. 

10. Before putting the electrolyte into the cells, the circuits connecting the 
battery with the charging source must be complete, care being taken to have 
the positive pole of the charging source connected with the positive end of the 
battery, and so with the negative iioles. 

11. The electrolyte is dilute sulphuric acid of a specific gravity of 1.200 or 2o° 
Baume as shown on the hydrometer at normal temperature (60^ F). If it is 
not convenient to procure this from the Battery Company, already niixed and 
ready for use, it should be prepared by diluting suitable commercial sulphuric 
acid, or "oil of vitriol," as it is more commonly called, with pure water. The 
acid, as well as the water, must be free from impurities, such as iron, arsenic, 
nitric or hydrochloric acid; this is absolutely essential. When diluting, the 
acid must be poured into the water, not the water into the acid ; the propor- 
tions of acid (of 1.840 specific gravity or G6° Baume) and water are one part of 
acid to five of water (by volume). The acid must be added to the water slowly 
and with great caution, on account of the heat generated ; the final density of 
the solution (1.200 specific gravity) must be read when the solution has cooled. 
The vessel used for the mixing must he a lead-lined tank, glazed earthenware 
or one of wood which has not been used for other purposes ; a new washtub or 
spirits barrel is recommended. 

12. The electrolyte should cover the top of the plates by l inch and must be 
cool when poured into the cells, which then shoukl never be allowed to stand 
for more than two hours, before the charging is started. 

13. The initial charge should be continued uninterruptedly, or as nearly so as 
possible, for about thirty hours at normal rate, or until the positive plates 
become a deep brown or chocolate color, the negative a light slate and the 
potential of each cell 2.5 volts (with current flowing), gas being freely given off 
from all the plates. The density of the electrolyte shoiild again be 1.200 sp. gr., 
having fallen considerably after being piit in the jars. 

14. At the end of the first charge, it is well to discharge the battery about i ; 
and then immediately recharge it. Repeat this treatment two or three times 
and the battery will be in ijroper working condition. 

15. When the battery is in regular service, the discharge shoiild not be car- 
ried below 1.8 volts per cell at full load; the charging should be started at once 
after a discharge and continued until the battery is full, as indicated by the 
four signs given above, i. e., potential, specific gravity, color, and gassing, the 
first two being most important. The cells must never be allowed to stand dis- 
charged. If, by chance, this should happen, then the charging must be pro- 
ceeded with at half rate ; the potential in this case at the end of charge should 
be 2.4 volts (0.1 volt less than normal) and the density of the electrolyte 1.200 
sp. gr. , the same as when the charge is at normal rate. Upon discontinxiing a 
charge the potential of each cell will immediately fall to about 2.2 volts, and 
then to 2 volts when the discharge is started. 

li) In order to determine whether the battery continues in good condition, it 
is essential that i)otential and density readings be taken at least once a week 
just before beginning the charge and also near the end. 



STORAGE BATTERY 



07 



(B) GEXEKAI^ INSTKl CTIOXS FOR CARE AIS^D OPERATION 
OF CHLORIDE STORAGE BATl^RY. 

To obtain the best results in the oi)eration of the battery, it is al:)solutely essen- 
tial that proper, careful, and methodical attention be ^aven to all the details of 
its operation, the same as is necessary with the generating machinery, and for 
this reason the following information and rules should be most carefully noted 
and followed; if this is done the total work in connection with the operation of 
the battery will l)e reduced to a minimum : 

1. Clnirgiiiti.—ln the charging of tlie battery, which .should preferably be at 
the normal rate, it is most important that it be continued until complete," but it 
is ecpially as important that it shoiild not ])e repeatedly continued beyond that 

l)oint, as not only will an unnecessarily rapid 
accimiulation of sediment and e.xcessive evapo- 
ration of the electrolyte result, but what is more 
important, the life of the plates will be very 
much shortened. 

At weekly intervals, however, it is advisable 
to slightly prolong the charge, in order that the 
electrolyte may be thoroughly stirred up by the 
prolonged gassing, and also to correct any un- 
eveniiess in the working of the cells, which may 
have developed. 

2. .1 complete datnje which in general should 
exceed the previous discharge ])y from 12 to 15 
per cent (in ampere hours) is determined bv the 
voltage and specific gra^^ty of the electrolvteor 
solution in the cells reaching a maxiinuui (not 
necessarily a fixed value), also bvthe amount of 
gassing, and by the color of theplates, the first 
two being the chief guides. 

8. Determiitation of maximum voltage and 
specijh' (/na-it ij.—\Y ith all of the cells in the 
battery in normal condition, with no impurities 
in the electrolyte and no material lodged between 
the i)lates or sediment touching them at tlio bot- 
tom, the maximum voltage and maximum specific 
gi'avity of the electrolyte is reached, when, with 
the charging current constant at the normal rate, no further rise or increase in 
either (voltage or specific gravity) during a period (if one-half hour is noted 
For instance, if the charge has been continued for five hours with a gradual 
continued rise in the voltage and specific gravity during that time, but with an 
additional one half hour of charging there is no further rise in either, then the 
charge is to hv considered complete. 

If the charging is at a rate lower than the normal, the interval during which 
no perceptible rise .should occur must be i)roportionately increased. 

4. The voltage at end of charge is not always the same throughout the life of 
.a battery, being dependent chiefiy upon two conditions, namely: the age of the 
battery and the temperature of the electrolyte, and for this reason it is most 
miportant m determining the completion of a charge, that the.se conditions be 
taken into consideration. 

\yiien first installed, the end of charge voltage %vill be 2.5 volts per cell, or 
higher, at normal rate and at normal temperature (70' F.). but as the age of the 
battery increases the point at which it will be fullv charged is gradually""lowered 
for corresponding rates and temperatures (see below) until, in many cases with 
both normal, it will have fallen to 2.40 volts, or even less, per cell. 

If the charging current is at the maximum rate, which should never be used 
except in ca.ses of emergency, where a rapid charge is necessary, tlie final 
vc>ltage will be approximately 0.0.-) volt pei cell above that of the normal rate 
\\ ith rates lower than the normal, the voltage at end of charge will be approx- 
imately 0.(1.) volt less for eacli one-fourth decrease in the rate, viz: 

If 2.50 volts at normal rate (100 amperes for illu.stration).'then 2.45 volts at 
three-fourths nonnal rate (75 amperes for illustration), and 2.40 volts at one- 
halt normal rate (50 amperes for illustration) 

The effect of changes in temperature on tlie final charging voltage is that it 
1^ noticeably lowered \\-ith an increase in the temi»erature above the normal 
( .0 ) and correspondingly increased with lowered temperatures, irrespective of 
the age of the battery. 



1 




I 




1 




I 


.iii^a*''^ 


1 


Htm0tfH&KtltP'^ ' 


I 


1 




1 





92. Type E-11 in Glass Jar, 



68 HANDBOOK FOR ELECTRICIANS. 

5. Voltage after charge and before discharge.— After the completion of a 
charge and the current is off, the voltage per cell will fall immediately to about 
2.15 volts, and then to 2.00 volts when the discharge is started. If this is not 
begun at once, then the pressure will quite rapidly fall to 2.05 volts, and there 
remain while the battery continues on open circuit. 

6. Specific gravity of electrolyte at end of charge and conditions affecting 
it. — As with the voltage, the specific gravity for complete charge is also affected 
more or less by the varying conditions during the progress of the life of the 
battery, in addition to the changes due to the evaporation and replacing of the 
water in the solution — the sulphuric acid not evaporating. 

In the beginning it should be between 1.195 and 1.205 sp. gr., at normal 
temperature, and with the solution at the proper height (f inch) above the top of 
the plates. 

Gradually there is a slight loss of the acid from the electrolyte, through very 
small quantities being carried off in that portion of the minutely divided spray 
that is thrown up during gassing at end of charge, which is prevented from 
falling back into the cell by the air currents in the room. In addition, some of 
it is absorbed by and acts upon the sediment which slowly accumulates in the 
bottom of the tanks, and so can not go back into the solution again. 

7. Restoring lowered specific gravity. — When this loss has become such that 
the highest reading that can be gotton at end of complete charge, all indi- 
cations of such being present, is ten points below the standard or what it was 
when first put into regular service, i. e., if it has fallen from 1.200 sp. gr., the 
original reading, to 1.190 sp. gr., then this loss should be regained by the addi- 
tion of dilute acid instead of water, when replacing evaporation. Under ordi- 
nary conditions it should not be necessary to add fresh acid oftener than once 
every two years, or possibly only at such times as the sediment is removed. A 
convenient density for this purpose is 1.400° sp. gr., because the proper density 
of the electrolyte will be more qviickly and easily attained by the use of this 
heavier solution, it containing double the amount of pure acid, in comparison 
with that of 1.200, so that, for instance, if four carboys holding ten gallons 
each, of 1.200 sp. gr. solution, would be required in any particular case, the 
same result could be gotten by using two carboys holding ten gallons each, of 
1.400 sp. gr. 

As it is essential for the successful operation of the battery that the electro- 
lyte be free from impurities (see under "Electrolyte" below) and as the ordi- 
nary commercial sulphuric acid is not of the proper degree of purity, it is very 
strongly recommended that all solution be purchased through the Storage 
Battery Company, which will undertake to supply the proper quality. 

If, for any reason, the required supply is not jirocured, the solution may be 
prepared by diluting specially treated sulphuric acid, or oil of vitriol as it is 
more commonly called, with pure water. 

In any case, a carefully collected sample (at least 8 ounces) should be sub- 
mitted for test. For water analysis one quart is required. 

8. Gassing and color of plates — Additional indications of state of charg- 
ing. — At the end of complete charge, in addition to the voltage and specific 
gravity reaching a maximum, gas will be given off freely from all of the plates in 
the battery, and the color of the plates should be a deep chocolate or dark brown 
for the body of the positives and a uniformly light slate or gray for the nega- 
tives. Provided the body of the positive plates is of the proper color, no atten- 
tion need be paid to the lodgment on the top of these plates or their projecting 
buttons, of a fine white powder that may be easily brushed off, the dark color 
then showing underneath. In fact, if these parts are of the deep chocolate color 
and no white powder is noticeable, it is an indication that the battery is being 
overcharged. 

This white powder is composed of particles from the plates, thrown off by the 
gassing at end of charge, which become sulphated and of a light color while in 
suspension in the electrolyte. 

9. If there are end cells in the battery, i. e., if some of the cells are so con- 
nected with the switchboard, that by either cutting them in or out, the pressure 
can be regulated, those that may have been successively cut into circuit on the 
discharge, should be cut out again on the following charge, as soon as they come 
up to a state of full charge and not be allowed to continually overcharge. If 
any of these cells are not used regularly or stand idle, they should be given a 
complete charge once a week. 

10. Counter electromotive-force cells. — In some of the smaller plants it is at 
times more suitable to provide for the adjustment of the pressure by means of 



STORAGE BATTERY 



69 



what are known as counter electromotive-force cells, instead of connecting a 
number of the cells of the battery to the regulating switch on the l)oar(l. These 
cells are made up of i)lain grids or i)lates without active material (storage 
capacity not being required), and do not receive any of the charging current, 
nor do they re(iuire the careful attention that end cells do. They should, how- 
ever, be examined from time to time, to see that they are not short-circuited, and 
if found so, the cause should be removed, the same as in the ca.se of the regular 
cells in the battery. 

11. Discharge. — As from the voltage and specific gravity readings the degree 
of charge can be determined, so likewi.se can the amoimt of discharge. 

13. Drop in foltiiye and sjtecijic fjravifi/ in<lication of amount and safe 
limit.— Dnr'm^ the greater part of a complete discharge the drop in voltage is 
slight and very gradual, becoming greater with marked rapidity near tlie end. 

The limit of discharge is reached when the voltage has fallen to 1.7.") volts per 
cell with current flowing at ordinary rates; in usual service, however, it is 
advisable to stop the discharge considerably above this point, more especially to 
insure a reserve in case of emergency. The fall in density of the electrolyte also 
serves as an indication of the amount taken out, and is in direct ])roportion to 
the ami)ere hoitrs discharged, thereby differing from the drop in voltage, whicli 

varies irregularly for different rates and degrees of dis- 

charge, and for this reason, under ordinary conditions, is 
to be jireferred in determining the amount of discharge. 

The actual amount of the variation in the strength of 
the electrolyte between a condition of full charge and of 
complete discharge is dependent upon the quantity of 
solution in the containing vessel, compared to the bulk 
of the plates. 

If a cell contains the full number of plates, the range 
will be about 35 points, or from 1.200 sp. gr. down to 
1. 165 sp. gr. With fewer jjlates, in the same size contain- 
ing vessel, the range will be about proportionately lessened. 

13. The coloi' of the plates is also a guide, as it is when 
charging. 

As the discharge progresses, the positive plates become 
lighter, and the negatives darker. 

14. Jnterral hetu-ccn discharge and charge. — When a 
battery is discharged it sh«:»uld be allowed to stand but a 
very short time (not more than an hour), if at all, before 
beginning charging again. 

15. Iiistrunicuts for vse with the battery. — For the 
successful operation of t)ie battery, there should be pro- 
viiled a i)ortable low-reading voltmeter, reading to three 
volts and calibrated to 0.02 volt, for taking tlie individual 
cell readings; two or more hydrometers, with scale read- 
ing from i.l50 up to 1.250 sp. gr.. and a portable lamp 
for inspecting the individual cells, in addition to the 
s\\-itchboard instruments, consisting of a voltmeter read- 
ing aiqn-oximately three times the number of cells in 
series in the battery, a two-way ammeter and a recording 
voltmeter with a scale tliat will clearly show the total 
range in voltage for l)oth charge and discharge, of the 
cells usually in circuit on the discharge. 

The recording voltmeter is especially desirable, because 
it enables the attendant to ea.'^ily and accurately note the 
progre.ss of charge and discharge, and determine, in con- 
junction with the hydrometi'r readings, after the manner 
noted above, the i)roper time to stop either. 

In addition to luring a guide for the charge and dis- 
charge, it furnishes a permanent record of the working 
of the battery. 

An ami)ere ho\ir meter, for recording the amount of 
both the charge and discharge, is also valuable, and \\nll act as a chei-k on the 
readings taken with the other instriaments. 

16. The elect rolijte is dilute sulphuric acid, and sliould be prepared by mixing 
suitable commercial sulphuric acid with pure water. It is absolutely essential 
that both acid and water should be free from impurities such as iron, arsenic, 
nitric acid or hvdrochloric acid. 




93. Long Flat Hy- 
drometer. 



70 HANDBOOK FOR ELECTRICIANS. 

If the user mixes his own solution, care must he taken to pour the acid 
into the water, not the water into the acid. The acid must be added to the 
water slowly and with great caution, because of the heat generated ; the final 
density of the solution must be read when the solution has cooled. 

The proportions of acid (of 1.840 sp. gr. , or 66' Baume) and water are one 
part of the former to five of the latter (by volume). The vessel used for the 
mixing must be a lead-lined tank, one of glazed earthenware, or one of wood 
which has not been used for other purposes. 

The water used in replacing evaporation should be of the best quality. If it 
is natiu-al water, drawn from the city or town supply or other source, it should 
be submitted from time to time for test. 

The water should be added to the top of the cells shortly after starting the 
charge ; not after finishing a charge or during discharge. Do not insert a hose 
into the cell with the idea of stirring up the electrolyte; this may result in 
piling up the sediment, and so short-circuiting the plates. 

The electrolyte must never be allowed to get below the tops of the plate. 

Should it be known that any impurity has gotten into the cell, steps shoiild 
be taken to remove it at once. In case removal is delayed and any considerable 
amount of metal becomes dissolved in the solution, this solution should be 
replaced with new inamediately, thoroughly flushing the cell with water, 
before putting in the new solution. The change should be made when the 
battery is discharged, and just before charging. If in doubt as to whether the 
electrolyte contains impurities, a sample taken at end of discharge should be 
siibmitted for test. 

17. Maintaining the battery in ^woper condition. — In order that the battery 
may continue in the best jiossible condition, it is essential, in addition to care- 
fully following the jioints noted above, that each individual cell in the battery 
be regularly inspected with a view to reducing to a minimum the chance for 
any of them working irregularly or getting low; also that cell readings be 
taken and recorded at fixed intervals in such form that consecutive readings 
can be easily compared and any trouble that may have developed be detected 
and remedied at once. 

For the individual cell inspections a portable lamp is required, so that any 
tendency for an accumulation or lodgment of material between the plates can 
be easily noticed and located. If the elements are in glass jars an ordinary 
lamp with extension cord attachment will be found most convenient and satis- 
factory, but if they are in lead-lined or other opaque tanks, then a lamp suitable 
for immersion in the electrolyte to the bottom of the tank will be necessary. 

When examining a cell, great care should be taken to look between all the 
plates. Any accumulation of material found between them should be removed 
at once. If it is from the plates themselves, remove by pushing down to the 
bottom of the containing vessel with a piece of hard rubber or -^ood, but if 
foreign matter is present, it should be withdrawn from the cell. Metal of any 
kind must never be used for the purpose in either case. 

These inspections should be so arranged that each cell is examined at least 
once every month ; if it is not convenient to go over the entire battery all at 
once, a sufficient number of cells may be looked into, say on one day a week, to 
get over them all within the month. 

In addition to the examination of the cells with the lamp, and to noting near 
the end of each charge whether all the cells are gassing equally well, readings 
of the voltage and specific gravity of each cell should be taken once a week at 
the end of the prolonged charge and so recorded, preferably in a book gotten up 
for the purpose, that consecutive readings can be compared. 



STORAGE BATTERY. 



71 



Rule a large sheet in the following form : 



Page 1.] 

RPECIFIf liUAVITV. 


VllLTAIiE. 


I'liK.i 2. 


Date, I'JOO. 


11-26 


12-2 


12-9 


12-16 


Date, 1900. 


11-26 


12-2 


12-9 


12-lfi 


Cell No. 










Kate. 


1(K) 
amperes. 


95 
amperes. 


KK) 
amperes. 




1 
2 
3 
4 
5 
6 


1201 

1202 

iiiiy 

12(K) 
1200 


1199 
1201 

Hits 

♦IlKT 

12(K) 


1200 
1202 
1200 
1201 
1199 




1 
2 
3 
4 
5 
6 


2.51 
2.52 
. 2.50 
2.52 
2.50 


2.49 
2.51 
2. 50 
*2. 27 
2.50 


2.60 
2.52 
2. 50 
2. 50 
2.49 


















. 

















59 


1 






59 










liO 


IIOK 


1200 
1201 


1200 
1201 




60 
61 


2.50 
2.51 


2. 52 
2.52 


2.51 
2. 50 




(il 1909 















From the above readings it will be noted that on 13-3, cell No. 4 is unusually 
low, being 15 i)oints in sjjecific gravity and 0.25 points in voltage lf)wer than at 
the previous readings, thus indicating something wrong with ihe cell, and on 
examination it would probably Ije found that the cell was short-circuited. After 
a good charge the cell again c-anie up, as is indicated by the reading taken on 
12-!>, no acid having been added. 

Tliese readings should be taken at the end of charge ; the voltage readings 
always when the current is flowing; oi)en-circuit readings are of no value. 

If any of the cells show readings lower than the normal and do not gas freely 
at end of charge, then they should be examined at once with a cell laini) to deter- 
mine the cause of the falling off. 

18. Gettiiuj loir cells into normal condition. — A cell which has been found to 
have gotten low will generally need inorti than the usual amoimt of charging to 
get it back into normal condition again, after the cause of the trouble has been 
removed. This may be accomplished in several ways. 

The first and simplest being to overcharge the whole battery, but care should 
be taken not to carry this to excess. 

The second, by cutting the low cells out of circuit over one or two discharges 
and in on the charges. 

Tlie third, by giving an individual charge while the other cells in the battery 
are on discharge; this may be done from a small dynamo, usually motor-driven. 

Before putting a cell that has been in trouV)le into regular service again, care 
should be taken that all the signs of a complete charge are present, viz: the rise 
in i)otential and specific gravity to the proper value, the gassing from the plates 
and the normal color. 

li). Si'ilinwnf. — Another cause for cells working irregularly, especially after 
they have been in service a considerable time, is the accumulation of sediment 
in the bottom of the jar or tank, to such a dejjth that it touches the bottom of 
the plates which then become short-circuited. 

For tliis reason the gradually inci'easing amount of sediment should be care- 
fully watched and removed before it gets dangerously near the plates. It must 
never be allowed to get up to them. 

As the ac-cumulation is usually greatest under the middle of the plates of a 
cell, care should be taken not to be guided by an examination under the end 
plates only. 

To remove the sediment, a convenient method, provided there is sufficient 
free .space at one end of the tank, is to "rake" it out from under the plates and 
then "scoop" it up. always using a device containing no metal in its construction. 

If, however, this method is impracticable, the electrolyte should be drawn off 
into clean containing ve.ssels, the battery previously having been fully charged, 
and the cells then flushed with waiter (the city supply may be used for this pur- 
pose) in such a way as to thoroughly stir up the sediment, the whole then being 
drawn off. the process to be repeated as often as necessary to remove all the 
sediment. If there is not sufficient drop to allow of siphoning, a pump should 
be u.sed. Pumps most suitable for this purpose are of the rotary type, with 
bronzed parts. 

After the tanks or jars have been thoroughly cleaned, the electrolyte .should be 
quickly reidaced. to prevent undue heating and drying of the negative ])lates, and 
also the long charge required by dry plates to bring them to a state of full charge. 



72 



HANDBOOK FOR ELECTEICIANS. 



In addition to the electrolyte -witlTidrawn from the cells, newmnstbe provided 
to make good that displaced by the sediment. This should be of 1.300 or 1.400 
specific gravity to counteract the effect of the water which was absorbed by the 
plates during the washing, and also to reduce the bulk of the new supply. 

20. Keeping electrolyte free from impurities. — Still another cause for irregu- 
larity in cells would be the presence of foreign matte*- in the electrolyte. If it 
is known that any impurity, especially any of the metals (except lead) or other 
acids, has gotten into a cell in other than very minute quantities, the electro- 
lyte should be replaced by new immediately, after the manner noted above under 
"Electrolyte." 

21. Battery used hut occasionally. — If, for any reason, the battery is discharged 
but occasionally, or the discharge is at a very low rate, a weekly freshening charge 
should be given. 

22. Putting the battery out of conimission. — If the use of the battery is to be 
discontinued for a time, say six months or more, it is very often best to take it 
entirely out of service by drawing off the electrolyte. 

This should be done as follows : 

After a complete charge, siphon off the electrolyte (which maybe used again) 
into convenient receptacles, preferably carboys which have previously been 
cleaned and have never been used for other kinds of acid, and as each cell is 
emptied immediately refill with water. When water is in all the cells begin 
discharging and continue until the voltage falls to 
or below 1 volt per cell at normal load ; when this 
point is reached draw off the water ; the battery may 
then stand without further attention until it is again 
to be put into service. 

23. Putting the battery into commission again. — 
To do this, proceed in the same manner as when the 
battery was first put into commission. After first 
determining that the polarity of the charging source 
has not been altered, so that its positive pole will 
still be connected to the positive end of the battery, 
put in the electrolyte and start charging at once at the 
normal rate, continuing until the charge is complete ; 
from tvventy-fj,ve to thirty hours at this rate will be 
required. The completion of this charge is determined 
in the same manner as are those when the battery is in 
regular service, as noted above. 

24. The attached form is recommended for recording the readings, which should 
be taken in duplicate, carbon paper being used to obtain the second copy which 
should be forwarded to the Company's office. 




94. 



Type Q=19 in Lead=Lined 
Pine Tank. 



(C) FORMS FOR KEEPING RECORDS AIS^D MAKING TESTS. 



1. Storage Battery Weekly Inspection Report. 

: Date, , 100 Time ■ 



.A.M. 
.P. U. 



Consisting of cells, type " Chloride Accumulator." 

Battery |^^^'iS'"«. at amperes. 

•^ (Discharging ^ 

Battery had been JD^s^ch^arging ""' I ^°^' *"""''** '*' 'i^'^'i'^K" •''t'^' "f amperes. 

Battery last inspected with lamp (date). 

Cells (Nos.) especially worked on during week 

Height of electrolyte above top of plates inch. 

Water was added to replace evaporation (date). 

Temperature of electrolyte °F; of air of battery room °F. 



Cell. 


Volts. 


Specific 
Gravity. 


Cell. 


Volts. 


Specific 
Gravity. 


Cell. 


Volts. 


Specific 
Gravity. 


Remarks. 


1 
2 
3 
4 
5 
6 
7 
Etc. 






31 
32 
33 
34 
35 
36 
37 
Etc. 






61 
62 
63 
64 
65 
66 
67 
Etc. 









STORAGE BATTERY. 

2. Test of B.vttehy of "Chlohide Accumulator" 

Consisting of ct-lls, type Locnti-il iit 



73 



< 


Datp. 


Time. 


No. of 

Cells 

in 

Cir. 


Total 
Volts. 


Volts 
per 
Cell. 


Amp. 


Amp. 
Hrs. 


Pilot Cell 


Itcnmrks. 


Volts. 


Sp.Gr. 


Temp. 






















Note. — Readings to be 
taken half hourly. Allot 
the cells to be in as near- 
ly uniform condition as 
l)ossible before the test 
is started. 

Pilot cell should he 
representutlve and in tlie 
main ])art of the battery. 


< 

i 























3. Test of Batteky of "Chloride Accumulator." 

Consisting of cells, type Located at 

























.,„ 


Test taken by 












Date, 


— . TO 

Time. p.m. 
|— a.m. 


TO 

A.M. 
""P.M. 


TO 

A.M. 
""P.M. 


— TO TO 

A.M. A.M. 
"P.M. ""P.M. 


— TO 

Time. a.m. 

""P.M. 


— TO 

A.M. 

""P.M. 


TO 

A.M. 
""P.M. 


TO 

A.M. 
""P.M. 


...TO 

A.M. 

""P.M. 




KKMAItK.S. 


Cell. ; Volts. 'Sp.gr. 


Volts. 


Volts. 


Sp.gr. 


Cell. Volts. Sp. gr. 


Volts. 


Volts. 


Sp. gr. 




1 
2 
.S 
i 
5 
6 
7 
8 
9 
10 

n 

12 
13 
U 
15 
16 
Etc. 












36 
37 
38 
39 
40 
41 
42 
43 
44 
4.5 
46 
47 
48 
49 
50 
51 
Etc. 












The rMdinps to be taken at 
the entl of char^^e and dis- 
fharpe; the voliape with the 
curreDt flowing, as recorcJed o?i 
the Ci) sheet; the specifii- 
gravity immediately after the 
current is off. 

Two columns for " Voits" 
under ** Diseharjie *' are pro- 
vided in ciLse the tirht set of 
readings is taken tiefore the 
battery is "down," or in case 
*'checK ** readinpi are df sired. 

The time when rea<lin>.-s are 
8t.arted and finished to be 
recorded at head of columns. 



74 



HANDBOOK FOR ELECTRICIANS. 



(D) GENERATOR AND CIRCUIT PAXEI. AND BATTERY 

PANEL. 

Generator and circiTit panel (fig. 95) and battery panel (fig. 96) for use in 
connection with chloride accnmnlators as designed and manufactured for the 
U. S. Gov't by the Storage Battery Company, Phila. V. M. switch: 1, bus; 
2, A + B discharge ; 3, A charge ; 4, B charge ; 5, + ground ; 6, — ground. The 
back connections^ will be evident. 




THE SWITCHBOARD. 75 

CE) COMBINED GEXERATOR AND BATTERY PAXEI. 

For use in connection with chloride accumulators where battery is charged 
and discharged in series, as designed and manufactured for the U. S. Gov't by the 
E. S. Battery Company, of Philadelphia. Voltmeter switch: Point 1, dynamo- 
point 2, battery ; point 3, + ground ; point 4, — ground. 






S; Ft 



€Z=t 



i ^ ^ 



E W 




\ >:c;:-Sl : I 




ii#ii>-'^'Hi'i'i#i'i#i'i>^ 

S1133 aN3 A.a3J_l*B 




76 HANDBOOK FOR ELECTRICIANS. 

Fig. 9oa gives the S. B. connections when a booster and end cells are employed 
in large installations. It is the most economical disposition shown. 

(F) PRECAUTIONS. 

1. Sulphating, buckling, and disintegrating of plates (positives are more sus- 
ceptible than negatives) are the three most serious troubles with storage cells in 
general, but they may be avoided ; if not too far gone they can be cured. 

2. Sulphating is a whitish scale that forms in patches due to overcharge ; to 
standing too long partially discharged, or to too strong electrolyte. It is also 
shown by loss of capacity and a higher voltage than the charge warrants. If 
slight, repeated slow charge below one-half the normal rate and discharge is the 
remedy ; if considerable, carefully scrape off the white scale prior to slow charge. 
No attention need be paid to a whitish loose precipitate which does not extend 
into the plate, as found by cutting into the skin with the point of a knife. 

b. Buckling or warping of a plate from unequal action on its two surfaces is 
caused by excessive charging or discharging rate or sulphating. To remedy, 
steadily press the plate between two boards 

4. Disintegrating of paste from plate results from sulphating, biickling, or old 
age and, if well started, new plates are the only remedy. It seldom or never 
occurs in chloride plates. 

5. The office of the storage battery is to form a reserve for feeding lamps, 
operating night signal sets, igniting fuses, etc., in case of accident to the 
machinery, and to illuminate the magazines for short periods, so as to avoid 
starting the engine. 

6. A well-managed chloride storage battery will last indefinitely on 6 per cent 
allowance of the cost for amortisation each year. Watt efficiency should be 
about 85 per cent ; quantity efficiency, 90 per cent. 

7. The normal rate of charge and discharge is about 12 amperes per square 
foot of positive plate counting one side only. The charge rate need not be 
exceeded ; the discharge rate, only in emergency. 

8. Gtiard against disturbing the plates in jars while connecting or disconnect- 
ing the lugs, and against solution falling from the hydrometer or stick, outside 
of the jar. 

9. Dry plates will keep indefinitely in a dry place. 

10. The deflection of a voltmeter across a connection should be no greater than 
for an equal length of Ivig. 

11. To charge a portable battery of few cells from a llO^volt lighting, a 550- 
volt trolley or an arc-lighting circuit by jilacing in series with the battery a bank 
of lamps or a rheostat, is well explained in figure 98., 

(a) The connection with an arc circuit, as in D, requires experience. The 
switch is so made that the contact arm A when thrown to the charging (two 
dotted lines) position shall not open the light circuit nor short-circuit the bat- 
tery A. Heavy wire resistance R has terminal C so spaced between B and D that 
the arm must touch C before leaving B or D. 

Or, R may be permanently placed in the arc circuit, its E. M. F. verified before 
switching in the battery and after the charge is finished and battery is opened. 
R is shunted out of circuit. The caution seems iinnecessary that while being 
charged the switch should be opened at the first sign of fluctuation or stoppage 
of the current. 



THK SWITCHBOARD. 



77 



lu the case of a battery of three cells or G volts requiring a charging C of 5 
amxjeres from an arc circuit of 7 amperes, i^ = 6 -^ (7 — 5) —'A ohms. 



^L^'5?^V1 A- 



II I 
I I 



BOL' MWl. 



HM. 




Di^gs^f^.B. 




R!A59^M XI • 




^otc KMrt Bwrrcrf. 



98. Charging: Few Cells. 

\b) In the case of the same battery charged froma UO-volt circuit the total 
resistance of lamps hot = (110 — 6) ^5 — 21 ohms. 

(c) In all cases the polarity and potential of the charging circuit must be 
known to be correct by means of the voltmeter before closing it on the battery. 
If no voltmeter is at hand, the polarity can be ascertained by dipiiing the termi- 
nals in salt water, when the greater flow of gas will ai)pear at the negative 
terminal which is the one which should be connected with the negative of the 
battery. 



Vir.— D. C. ELECTRIC MOTORS. 



(A) ESSEJS^TIAI. PRI:N^CIPLES AND CLASSIFICATION. 

1. Any D. C. dynamo supplied with current from an external source will 
operate as a motor. The lead of a motor, if any, is backward, not as in a 
dynamo, forward or with the rotation. 

2. To get the direction of rotation of any conductor on the motor arma- 
ture's surface, hold the left hand with its thumb and first two fingers extended 




99. W=e Multipolar. 



at right angles to each other, so that any one of the three lies parallel with the 
conductor i^ointing in the direction of the current through it, and so that 
another points in the direction of the lines of force of the 
field magnet ; then the third will point in the direction the o 'iS-J'nPouT 

conductor is urged. 

3. Back electromotive force. — The armature of a motor 
revolving in a field, owing to an external supply, has an 
E. M. F. set up in it precisely the same as if it were 
revolved as a dynamo. This E. M. F. or (e) has (from the 
rule with the right hand) a direction opposite to that (E) 
which actuates the motor, and is therefore called back or 
counter E. M. F. The motor's power varies directly with 
the resultant E. M. F., i. e., with {E—e). Ex. If 100 volts 
be applied to the brushes of a motor of 2 ohms internal 
resistance, and if the armature be clamped to prevent 
rotation, the current would be 50 ampei'es. But if the 
armature is allowed to revolve, a counter (e) will be set up 




100. Motor Left Hand. 



of say, 96 volts. The current then through the motor is 



(100— 96) A^olts 



=2 amperes 



2 ohms 
and the power expended is 2x100=200 watts. 

4. Efficiency. — The po^w^er input (C amperes X E volts) is always eqiial to the 
useful output or power at the pulley (torque in lbs-feet X revs, per sec.) 
plus the energy wasted per second to overcome olimic resistance, friction, 

(78) 



ELECTRIC MOTORS. 



^9 



windage, hysteresis, Foucault and eddy currents. The total wastage amounts 
to 10 or 15 per cent. Efficiency of a motor = useful output -r- input = 80 to 90 per 
cent usnallv. 

5. IVIodern D. C. motors are usually wound for a constant potential supply of 
500 volts for several miles transmission, 220 volts for a few thousand feet, and 

110 volts for a few hundred feet as in 

forts. Like modern generators, they us- 
ually have 4 or more removable poles 
projecting inwardly from an outer field 
.st?el casting support toward an iron- 
clad armature, i. e., one in' which the 
conductors are sxink and bound below 
the surface in slots parallel with the 
axis. Displacement of the winding is 
therefore impossible. 

In the construction both field and 
armature coils are formed on moulds, 
insulated and laid without ])ending on 
tlieir cores, which are laminated trans- 
versely to their main cnirrents. The 
armature core has air ventilatin.g ducts 
])arallel and perpendic-ular to the axis 
to which it is rigidly held by a spider. 
The commutator has large diameter and 
many bars insulated by mica. The 
brushes are carbon, radially ])laced with 
little or no lead and are si)arkless from 
full load to no load ^Wthout ad.justment. 

G. Earli. class lias a spcciid use.— jQOa. W=e Core of M. P. Motor. 

For constant current supply, motors are 

always series wound ; for constant potential, they are series, shunt or compound 
Avound. 

(fl) The series motor (fig. 101) has great starting torque (force X lever arm), 
changes its speed greatly for small changes of load, does good work a't the dif- 
ferent speeds, races dangerously without load, and is regulated by a rheostat in 
series witii it. If its supply is constant current, it may be safely overloaded to 
the point of stopping; if constant i)()tential, it may run one-half hour on 25 per 
cent overload. It is suited to variable speed work as in railroads, automobiles, 
hoists and machines which require increased torque when slowed down from 
overload and have au attendant. Series motors run parallel across constant 
potential mains, v»-ork well on sei)arate work; on Joint work each must be geared 
(not belted) for a speed corresponding to its share of the voltage. 






Cownter OocKwiao 



101. Series \%'ound. 



{h) The shunt motor (fig. 102) has moderate torque at starting, gives nearly 
constant speed with varying load, falls in sjieed only a few per cent from to 
full load, is largely self -regulating, and suited to blowers, lifts, and lathes. The 
armati;ro and field circuits lie in parallel across the mains, and the speed can be 
regulated by a starting box in either one or in both; the rheostat in the arma- 
ture circuit is essential at starting to i)revent a destructive ctirrent. Several 
shunt motors of like voltage may be placed in parallel, even of unlike power, 



80 



HANDBOOK FOR ELECTRICIANS. 



either to work separately or each to do its part on one shaft ; or in series, to worlc 
separately. 

(c) A compound motor (fig. 103) is cnmiilatively or differentially wound— a 
compound dynamo as a motor has the latter winding. The former kind is com- 
ing into use. It has increased torque at slower speed, is partly self -regulating, 



Sta'ting Rheostat 



Stinting nt-ieostat 




102. Shunt Wound. 



and is adapted to work where heavy overloads occur and close regulation is not 
important, such as for printing presses and hoists. Their supply is constant 
voltage only. 

(B) TIEGULATI:N^G and PROTECTIIS^G APPARATUS. 



1. When a motor armature is at rest there is no counter E. M. F., and if the 
potential of the supply were closed upon it, the current would be destructive. 
Hence, a starting and stopping rheostat (fig. 108) is always put in series with the 
motor and its resistance is gradually cut out as the 

motor gains speed and counter E. M. F. 

When a starting box has not wire of sufficient 
cross-section to carry the motor current for any 
length of time without overheating, the switch must 
not remain on a point longer than two or three sec- 
onds. When the rheostat wire is large enough to 
carry the current indefinitely, the box is a speed 
regulator or controller. 

2. The motor is slowed down and finally stopped 
by turning the same contact arm to throw resistance 
into the motor circuit and thus gradually to dimin- 
ish the current from full strength to zero. To open 
the circuit as at the main switch while full current 
is flowing would endanger the insulation from the 
induced extra current. 

3. In addition, a motor requires to be protected 
against sudden excess of current by an overload 
automatic circuit breaker in one or both of its feed- 
ers, which is quicker and more certain than a fuse ; 
also by an underload automatic circuit breaker against 
the fall of the current or of the potential below a 
certain limit due to a cross or other accident which 

is liable to be followed by a rush of full current that Shunt 

would destrov the motor at rest. 103. Compound Motor. 




ELECTRIC MOTORS. 



81 



(n) Diagram of General Electric S. and S. rheostat (fig. 104) with automatic 
release (underload C. B. ) in armature circuit of small series motor. Box is 
shown for small shunt motor. 

J^ £D. 



Release rT^agnefc 




104. Diagram of S. and S. Rheostat. 
(h) Diagram of General Electric S. and S. rheostat (fig. 105) for larger series 
motor with underload release magnet in the armature circuit and magnetic 
blow-out at the first step ; stops on left-hand side are connected with middle 
pivots of coils on right-hand side. 




mrnr 



105. Diagram of S. and S. Rheostat for Larger Series Motor. 

(c) The armature of the retaining magnet is adjusted by means of the screw 
and nut to hold at a c-urrent ecjual to about 5') per cent of tiie full-load amperes 
of the smallest size of motor with wliich the rheostat is used. Therefore these 
series motors must be loaded to about one-half their capacity, or the armature 
will not lie lield by the magnet. 

Boxes for S. and S. rheostats (fig. 106) for shunt motors, two larger showing 
magnetic blow-oiat. 



82 



HANDBOOK FOR ELECTRICIANS. 



(d) Starting and stopping rheostat (figs. 107-8) for shunt motor with no 
voltage (underload) , automatic circuit breaker in the field circuit, with overload 
release and magnetic blow-out in the main, and with switch shown in the "On" 
position in fig. 108. Mid-points of resistance coils are connected. 



^ 


I ■ ._ 


nw^ 


^s>/ ■ 


■P 


^^^^^^M 


H 




9 




^^^^^^H 


I',', 


' imp 




^H 


'f>\ 




H 




m 






n 




^^^^^ 







107. Starting and Stopping Rheostat for Shunt Motor with no Voltage. 




/Trrnature 



108. Wiring of Starting and Stopping Rheostat. 



■om Supply 
Circui't 



Cut-Out, 



Switch 




^mnat-ure 



De-tails of Release TDa^net 




1 


.e 


] 




M 


1 




^ 




K 




© e 


' V ^' 


B V 


- 


^ 


cl 



!((<>. kheustat and Cunncctiuns. 



ELECTRIC MOTORS. 



83 



The s^^tch IS moved gradually clockwise against the action of the spring and 
held by the U. L. npper magnet. If the potential of supply falls off Ha %> per 
cent, the magnet releases the armature on the switch which flies to the -'Off" 
position where the arc, if any. is Idown-out. 

If the current exceeds the allowable limit in the O. L. or lower ma-niet of 
heavier wire, the armature, lift,.,] against the two pins, short-circuits the 
underload magnet which then operates as above. The .spindh' of the switch or 
ontact-arm is connected by 
wires with one side of both mag- 
iK'ts an,l the left pin. 

(.) Figs. 109 and 110 sh,)w 
rlienstat and connections for 
large sliunt motor, with under- 
load, circuit breaker of differ- 
ent form, wlio.sc details are 
plainly indicated in separate 
cuts. 

(/) Automatic O. L. and 
U. L. circuit breaker (fig. Ill) 
IS held in the "On" position 

against tlie tension of a spiral 

spring in the hub. 

G. Directions f,)r installim,' 

rheostat s are as fulh )ws : 

[(i) If the rheostat must be 

attached to ironwork of any 

kind, special care should be 

taken to thoroughly insulate it 

from the iron. 
Attach the small rheostats 

Avhich have no magnetic Idow- 

ont, to the wall with the retain- 
ing magnet on the right-hand 

side and the onnection ter- 
minals at the bottom. The 

large rheostats, with magnetic 

blow-out, sliould be installed 

with the magnets at the top 

..th,.rwise the arc at the blow-out may cause trouble. 

..';'. .:^;^^".-;'('"JA.-Tlio rlieostats are adjusted so that the arm will return to the 

Ui ^ 'k S HeS.^l'l^i^n '^i " '' '^J^T ""^ '''' ^^^1'^ ■^''■' ^eneran- Snd to be 
V- li V <^-'"fVi'"iKtliem, the arm .still works too .stitHv slacknu tli.^ •i,1-iii«Hiicr 

annwIna'dret^utofVr-'V ^1-- nuts must be ^ks^ciu.d^-\oclS!jo?Sf 
.um \\iii .ig.im get out ot ad.pi.stinent. 

„mT !" 'i"''i'?^?'f, ^^ *'^^ i-etaining magnet is adjusted by means of the screw and 

Zlheo^tVulS:'""''^' ""'"'^ ""^""' ""' the-'smallestlsize of motor ;SwhTch 

Sonietime.s h,nvever, th.- field current may be less than the avera-e and it is 

?he field cun/t-^^^^^^^ ^"*^' ^^\' ^'^'l^'asing of the armature when 

xiiL neid cunent l.iils to at least one-quarter of the ayerai;,- and if anvcbnxrei^ 
uade in tlie adjustment to have the armature hold lu.uv; v rely rid s i nM 
r. ..; ;-''t'r"^''^ "^?*T' *'^^'" ^'""in^- nS the supply, f cur-; t,seet 

tl It twilnnt.l f •y.inature does not release by that time there is danger 
tn.it It AMll not do so in time to protect the m,itor * 

„„>nf ^^f'"" ■'''■*'" "''^^'^^'-''^^^ ^-^ hold .securely with the ram-,, of adiust- 
n -V^ *i '' "•'''' "''''^;"r* "I"^"^ ^" '^'"t ^'"^ c-on,litions. Th.< ove r ud rehSe is 
b • r t:^ f '^'h"'''"' ""^ *''^ •'^'•^^''^' '"'^'*^^' ^^"- "n'u.ture, to operate w.-n the amperes 

rhi.s[at AA^l^buSi" "" '""^ '■''"■"^* "^ *''^ ^^^S^«t "^ot"r for which the 

L 1 ",; V ' •,, 1 ' ''^'^'''"^- ^" "•'* ^^^'^^ ^^»'' li"P for current by t.mchiuir the 
?1 ds d'T' '^'" '"■"" ^"\'^ ^}''''' allowing it to go back to the " Off p, Si , 




F 
111. Automatic O. L. and U. L. Circuit Breaker. 



84 



HANDBOOK FOR ELECTRICIANS. 



(rf) Renewals.— If. the first step which is of copper and hexagonal in shape 
becomes burned, it may be removed by imscrewing it and substituting another. 
The arm may also be easily taken off and smoothed or renewed. 

(C) OPERATION AND CAKE OF MOTORS. 

STARTING. '■ 

1. See that all nuts and parts are tight, that connections are correct, that 
the commiitator is clean, that the brushes are properly set, and that the 
starting switch is in the "Off" position. Turn, if possible, the armature by 
hand, to see if it is free. Close the main switch. Turn the rheostat switch 
steadily clockwise until it strikes the automatic release, so that the motor starts 
slowly and increases uniformly to full speed, taking about one-half minute to 
turn the switch. If the motor is new, run it empty for a time and see that all 
parts operate properly when the motor is partially and fully loaded. 

If a motor fails to start after beginning to cut out the resistance, turn the 
switch off to prevent accident before beginning to explore. With a voltmeter, 
or with the hands on low potentials, ascertain if the supply is present. If it is, 
take off the load, close the main switch, and see if the armature moves. If it 
does not, proceed from the mains with a voltmeter iia search of a broken circuit. 
The break may be in the rheostat. 




112. W=e S. and S. Box. 

If motor terminals show potential and poles have no magnetism, there is a 
break in the field of a shunt or compound motor, or between the terminals of a 
series. But if the poles are magnetized, see if brushes are at the neutral point 
and pressed down, if commutator is clean, if adjacent poles are not alike, or if 
coils have not a short circuit. 

RUNNING. 

2. (a) See that the oil rings or feeds distribute oil properly, that the belt 
runs in the middle of the pulley without tendency to thrust the armature 
toward one end, and that no part gets overheated. The heating of any part 
is probably normal if its temperature is 110" F. or less above that of the sur- 
rounding air after several hours' continuous run on full load, as tested by a 
thermometer placed upon it and surrounded by waste. The danger point has 
not been reached if the hand can bear long contact without discomfort. Hot 
coils are xisually due to overload, short or partly open circuit. Commutator and 
brushes often g'et hot from sparking or friction. 

{h) From time to time, or whenever the bearings show signs of heating, draw 
off the oil and replace with new by bringing up the level until the rings flush the 
shaft freely, care being taken not lo overflow the bearings. 

A hot box is due to 'poor oil, grit, rough-bearing surface, tight box or belt, 
shaft bent or out of line, or overload. 



ELECTRIC MOTORS. 



85 



(c) The usual load causes a certain rise of temperature in each part which is 
well known to the watchful attendant, and any increase of that amount requires 
immediate correction without, if possible, stopping the machine. If smoke 
appears, damage has been done. 

{(I) Irregularity of speed may be expected in a series motor whose load varies. 
But a .slinnt motor changes speed slightly for large variation of load ; if over- 
loaded it heats. Abnormally low speed indicates overload, short circuit or a 
defective contact. 

(e) Keep all parts of the motor free from dirt, damp, waste oil and carbon dust. 

STOPPING. 

3. Turn steadily the rheostat switch contraclockwise to the open stop ; then 
open the main switch. The order is the reverse of that in starting. Finally, 
take the same precautions as in leaving dynamos. 

4. ' ' Faults " in motors, together ^vitll their caiises and remedies, are for the most 
part, the same as for dynamos (page 52). The motor <m account of its duty is 
not, as a rule, so accessible as a generator; its care, equally important, is more 
likely to be neglected. 

Prevention, not cure, is the rule for motor or dynamo troubles. 

Dirt, sparking or overheating usually affords conclusive testimony regarding 
the attendant's fitness. 

Oil cans, tools, or loose iron near the motor in operation are liable to be drawn 
into the armatiire. 

To reverse a D. C. motor, reverse the current through the armature (usually) 
or the field — not both. 

The voltage of supply shouldbe within 5 per cent of that for wliich the motor 
was built. 

Excess voltage to shunt motors will heat the fields and somewhat increase the 
speed; scant voltage ^^^ll heat the armature and lessen the speed. 

Remember main switch first, rheostat last in starting; rheo.stat first, main 
switch la.st ill stoi)ping. 

Do not keep the rheostat switch long on one stop, except the end ones, unless 
the rheostat was built to carry the full current indefinitely as a regulator or 
controller. 

Oil reservoirs may be half drawn every three or four weeks and refilled with new. 

High-grade, dense, mineral oil, free from grit, is the proper lubricant; after 
filtration it may be reused. 

Keep posted all motor circuits and manufacturer's directions. 

A ."^eries motor always runs reverse to its direction as a generator; a shunt, in 
the same direction ; a differential compound, according to the stronger field. 

(D) SPECIAL FORMS OF MOTORS IX SERVICE, 

1. (a) The Leonard motor control for guns turrets, jiassenger elevators, etc., 
avoids violent stresses, bad sparking, and affords complete control with ])recision 
of stoppage. 

(b) In fig. 11:3, M is the 
motor whose field is con- 
stantly excited direct frcmi 
the mains. G is the genera- 
tor, likewise excited, but 
through the reversing field 
rheostat ( '. The brushes of 
M and (/ are permanently 
connected. 

(c) To start the motor the 
generator's field is weakly 
excited. As resistance is 
cut out of C, G delivers 
stronger current to M and 
increases the speed. The 
rheostat contact arm is 
divided by insulation at the 
pivot. Turning it to left 
reverses the G field and Ms 
motion. 

2. The recording watt-hour meter (fig. 114) in general use is a compound 
wound ironless motor, whose main field coil carries the main service current, 
and whose armature of fine wire lies with dead resistance across the mains. 




113. System for Training duns 



8G 



HANDBOOK FOR ELECTRICIANS. 



The revolutions varying as the C and E of supply and therefore as their pro- 
duct, are recorded as units, tens, etc. , on the dials. The shunt field is added to 
compensate for friction. A copper disc on the armature shaft revolves between 
the poles of an adjustable magnet, which can slow down the motion 16 per cent 
or less as desired. 




114. Measures Electrical Energy. 

3. Dynamotors, motor generators, and boosters are rotating transformers of 
direct current having a dynamo and a motor armature winding and two com- 
mutators usually on the same shaft. 

(a) The dynamotor has two armatures, or two separate windings on one 
armature revolving in one magnetic field. Its place in the Teazer system for 





115. Thompson's Recording Watt Meter. 



SUPPLY MAIN 

116. One of the Special Motors. 



starting a main motor without taking excessive starting current from the 
mains is shown by "Teazer Armature " in fig. 116. 

The left coinmutator belongs to the motor winding on the armature ; the 
right commutator, to the dynamo winding which has about one-fifth of the 
potential of the motor's winding. At starting, the Teazer dynamo supplies 
about one-fifth of the main voltage to the main motor, giving proper torque -at 
low speed without draining more than about one-fifth of the current from the 
supply mains whicli wouhl be taken without the dynamotor. When the mam 
motor has reached the highest speed attainable in this way, it can be switched 
to the supply mains and the Teazer circuit switched out without excessive drain 
from the mains. 



ELECTRIC MOTORS. 



87 



(b) The motor generator (fig. 117) has two armatures revolving on one shaft 
in sen-irate fields The motor commutation is at one end, the dynamo s at the 
other It is not so efficient a transformer as the dynamotor, but its dynaino 
volta-e may be given greater range and its modes of construction and operation 
are simpler in charging batteries, electroplating, supplying telegraph trunk lines 
or current to laboratories. 




117. Motor Generator. 

(e) A booster is an electrically or mechanically driven transformer whose 
dynamo commutator is in the main circuit at a distant point to raise the voltage 
there Both the main and generated currents flow together m tlie dynamo 
armature winding, which has, therefore, very thick copper. Boosters are 
placed, for instance, at the ends of long feeders running from the same bus bars 
as short feeders, to keep the potential the same. 



VIII ELECTRIC HOIST WITH AUTOMATIC SAFETY STOP. 



It is applied to two platforms, G G, either of which is drawn upward, while 
the other descends, by a winch driven by a motor through worm or train gear. 
A 5-horsepower motor can raise 2,000 pounds counterweigh ted by 600 pounds of 
the other platform at the rate of 1 foot per second. The design is simple, inex- 
pensive, and the motor and hoist are fairly well protected. 

1. Mis the motor with both series and shunt fields, the latter being excited 
when M S is closed. B S is a three-pole reversing switch shown in position for 
the right-hand platform to ascend. 

2. The controller has a starting rheostat, Rh; a hand lever, W; a spring lever, 
V; an underload release, U L ; and an overload release, O L. The magnet U L 
depends for its excitation upon the voyage of the motor terminals and also upon 
the integrity of its circuit at any one of the four points — O L, R S, E, or F. The 
main circuit from M S is through the electro-magnetic brake E B, series fields 
OL, to the contact i)iece b ; when flie lever V is held dowii hj U L magnet, the 
circuit is closed from h through d, V, W, B h (or direct after the motor has 
attained full speed), to RS, 3Ito3IS. 

3. The main circuit is broken either when the lever V is released (e and / taking 
the spark) , or when Wis moved to the left (k and I taking the spark) . The lever 
V, when released by U L, is carried to the right by the spring at its axis until it 
strikes W. The rheostat may be designed for running the motor continuously 
at different speeds, or as a starting box not to be in the circuit longer than 
thirty seconds. 

4. S isa baby switch held open by a spring. Its object is to close, if desired, 
the U L magnet circuit when open at E or F. 

5. A and A are the devices for automatically bi'eaking the circuit through UL, 
and thiis the main circuit when the platform ascending strikes the lug g, which 
is adjustable on the bar sliding in guides /;. On the lower end of this bar an 
insulate copper wedge makes, when down, contact between two copper terminals 
at E or F, and breaks it when up, thus making or breaking the circuit through 
U L. E and F are alike and adjustable vertically 6 inches. 

6. The right-hand platform is at its upper level, the left-hand is at its lower ; 
the circuit through armature M has been broken and Fis up against W. If now 
we try to start the motor without reversing R S, the circuit through M will still 
be open at E. But throw R S down and the circuit through U L will be closed 
at F, and the left-hand platform can be raised. 

7. To start the motor at all, W must always be brought up to the left, pushing 
V before it until held by the underload magnet U L ; then W may be moved to 
the right, closing the circuit first through R h and at last without it. 

8. When the left-hand platform, on nearly reaching its upper level, engages g 
and opens F, the main circuit will be opened at h and the motor will stop. 

9. If it is necessary to move the platform farther up after the circuit has been 
broken at E or F, the switch S may be closed and the platform may then be 
moved by the motor. So long as S is closed F will not be released except for no 
voltage or overload. 

10. The motor may be slowed down or even stopped by moving W to the left, 
provided R h is large enough to carry the current. 

11. The electro-magnetic brake on the gear wheel next the motor armature 
automatically clamps it whenever the main current ceases and the motor stops. 
It gives a quick stop for heavy or light loads. 

1 3. If the electric machinery is disabled the motor is quickly thrown out and 
the platform can still be raised by a crank handle and gearing. 

(88) 



ELECTRIC HOIST. 



89 




IX.— SEARCH=LIQHT PROJECTORS. 



THE 60-INCH DIAMETER SCHUKERT SEARCH LIGHT 
AT FORT MOIS^ROE (Fig. 120). 

With 150 amperes, at about 60 volts, it has 194,000,000-candlepo\ver. On a 
clear, dark night a jierson within its beam, 12 miles distant, can read ordinary 
print ; it lights up an object 2i miles distant with the brightness of the full moon, 
and it will enable a person near the projector to distinguish, with the aid of a 
glass, a vessel at 6 miles distance. 

(A) THE U. S. GOVERNMENT PROJECTORS 

Are supplied by the General Electric Company in the following sizes or 
diameter of reflector : 



Control. 
(Hand, H; pilot 
house, P; elec- 
tric, E.) 


SlZK. 


Current. 


CARnONS. 


Amperes. 


Volts at Arc. 


Positive — 
Cored. 


Negative. 


H. or P. 

H., P. orE. 

H. or E. 

H. or E. 


18" 
24" 
30" 
3G" 


.35 

50 
80 
130 


4T-.'J0 
48-52 
49^3 
50-65 


13// X ii}4" 
l"'"'xl2"" 
l%" X 12 " 
l%" X 12 " 


%" X 6" solid. 
%" X 7" cored. 
%" X 7" cored. 
1" X 7" cored. 



All are fitted with true parabolic ground glass, silver-plated mirrors, as speci- 
fied for standard use in the Navy Department. The light reflected from the 
parabolic mirror is whiter and more penetrating than from a spherical mirror. 




121. Rheostat for U, 



S. Qovemment Projector. 

(90) 




!.(). oO-inch Diameter Schukert Search Li^ht at Fort Monroe. 



SEARCH-LIGHT PROJECTORS. 



91 



All proiectors are fitted with horizontal automatic ratchet-feed focusing lamps. 

The lamps are clesiRned to throw the greatest possible amount ot light ..n the 
reflector, and screen shutters are provided to prevent the direct rays trom eavmg 
the projector, so that all the rays of light are reflected and sent out parallel 

Bith posit ve and negative carbons are fed automatically at the same time 
and are so proportioned that the arc remains m the focus of the mirror until 

thev are entiivlv consumed. _ . , i i • . i i • i. 

Th carbon hohlers <,r c-arriages are designed for vertical and horizontal adnust- 
ment of the carbons, and by means of a magnet fastened on the insid." ..t tl.e 
pro cctnrandsurr.)unding the arc on all sides but the top the arc is made to 
burn steadily near the center of the carbons and in focus with the mirror. 

In order to obtain the best results the carbons must be liard, h.miogeneous 
and of the best quality. Soft carbons fuse and make •'niushr.nmis which cut 
out a large portion of the light and prevent the arc trom burning steadil.N . 

All pr^riectors are designe.l to oprrate on direct "Yi-^^"|."^^'"?^^^"^^7^>^^:;;:7"^"- 
A regulating resistance of G. S. ribbon (fig. l'2l ) is placed m .series with the 1 np 
to reduce the voltage, SO or 11(», to the proper potential, which varies from 40 to 
GO volts, according^o the size of the lamp and current consumed. 

(B) MKTIIODS OF COXTROI.. 

1 The beam of light from the hand control projectors can be trained 
vertic-allv or h.n-i/ontallv bv the operator standing at the projector and moving 
Jlu barrel in the dcsire.l direction with the handles. A star wheel, mounted on 
the arm. clamps the (piadrant part of the 
trunnion and acts as a locking device by 
means of which the barrel of the projector 
mav be held at any desired angle. 

2" The pilot-house control projectors, en- 
tirelv of brass (fig. 122), are mounted on top 
of tlie pilot or other house and operated from 
within. Both horizontal and vertical move- 
ments of the beam of light are accomplished 
by means of the same lever which is located 
conveniently within reach of the pilot. The 
projec-tor mav be locked at any desired angle 
l)y turning tile handle of the lever so that it 
screws against the riuadrant like a set screw. 
It has conductor rings and In-ushes in the 
base so that the projector can l)e rotated in 
a horizontal plane. If the projector is to be 
located at some distance, tlie above mech- 
anism is adapted to rope belting. 

3. Electrically controlled projectors (fig. 
123) mav be operated from a distance. They 
have two electric shunt motors mounted in 
the base of the projector, one motor operat- 
ing a train of gears controlling the vertical 
movement, and the other motor operating 
another train of gears controlling the hori- 
zontal movement of the i)rojectors. These 
motors are regulated by a controller c(m- 
venieiitlv located and connected to the pro- 
jector by seven conductors. The movement 
of the beam of light corresponds to the 
movement of the handle of the controller, 
and both horizontal and vertical movement 
can be obtained at the same time. On 
releasing the handle of the controller, it is 
brought back by a strong spring to the 
lu'utral position, short-circuiting the anna- 
tures of the motors and holding the projector locked in position. An electrically 
controlled ])rojector c-an also be operated as a hand control projector, by open- 
ing the circuit switch on top of the controller and releasing the clutclies con- 
nected to the motors in the base of the projector. 

The drum rotates on its trunnions and can be elevated 70' above and lowered 
30' below the horiz<mtal position. The turntable can be revolved freely in 
either direction in a hoi-izoutal plane. 




122. Pilot=House Control. 



92 HANDBOOK FOR ELECTRICIANS. 

Witli electrical control, the highest speed obtainable in the horizontal plane 
is a movement of 360° in thirty seconds, and in a vertical plane lOOMn sixty 
seconds. The motors may be operated at four slower speeds and also by steps, 
the angle of each step being less than a degree, that is to say, about one third 
of the area covered by the beam. 

4. In genera] the projector is designed to take either a spherical or a parabolic 
mirror. The trunnions being mounted on slides, allow the drum to be balanced 
with either mirror. The mirror is so mounted in a brass frame that it is securely 
protected against concussion and provision is made for expansion due to heat. 

The plain front door, used when long range and small area of beam are 
required, is composed of strips of i^late glass. 

When projectors are required to furnish a beam of light covering a wide area, 
at shorter range, the front door is made up of strips of glass ground plano-convex, 
each strip being a lens, with the convex side oiitward. The beam of light ijass- 
ing through this door is diverged, making it wider but not increasing its height. 
These diverging doors are for either 10", 20°, or 40° divergence for any projector. 

(C) NUMBER AND NAMES OF PARTS. 

1. The hand-control U. S. projector is complete with the following parts: 
The base with all the gears; turntable with arms and drum; 1 mirror; 1 front 
door with plain glass ; 1 front door with diverging glass ; 1 box f oj- front doors ; 
llamp; 1 rheostat; 1 canvas cover ; 125 positive carbons in tin boxes ; 125 nega- 
tive carbons in tin boxes ; 1 extra set of plain glass front door strips in plain 
wooden box. One tool box containing the following articles : 1 crank-handled 
socket wrench for lamp feed; 1 wooden-handled socket wrench for adjusting- 
carbons ; 1 smoked glass with frame ; 1 dust brush ; 1 small dusting brush for 
lamp ; 1 chamois skin for polishing mirror ; 1 spare spring for starting magnet ; 
1 spare spring for feeding magnet ; 1 contact spring ; 1 contact screw ; 2 round 
smoked glasses ; 1 round ground glass ; 2 pairs of carbon holder clamps, screws, 
and washers; 43 extra lava insulators ; Ismail wrench for 8-32 and 10-32 niits. 

2. The pilot-house controlled projector has the same apparatus, except pedes- 
tal, but in addition rope and guide pulleys. 

3. The electrically-controlled projector is furnished complete with the same 
parts as the hand-controlled projector, together with the following additional 
parts : 1 controller stand and canvas cover ; 1 controller cable 25 feet long, with 
connecting plugs at each end ; 1 controller receptacle ; 2 pairs of carbon brushes 
for motors ; 2 20-ampere fuses for controller ; 6 8-82 nuts. 

(D) INSTAEEING PROJECTORS. 

The arrowhead, which is cast or painted on the base or the pedestal of the 
projector, should point aft. Otherwise, the maximum allowable motion of the 
projector can not be obtained on account of the stop pin which is inserted to 
prevent twisting the cables. 

• The current should be led directly from the switch board in the dynamo room 
to a switch which should be mounted near the projector. A rheostat should be 
placed in series in the circuit, and also an ammeter to indicate the current. 

1. Hand control projectors are shipped assembled, so that they may be imme- 
diately bolted to their place. When the lamp is inserted and the necessary con- 
nections are made to the supply wires the pi'ojector is ready to operate. 

2. For pilot-house control projectors, select a desirable position on the house 
roof for the location of the projector, and cut a hole through the roof nearly the 
diameter of the inside of the low base ; disconnect the handle and bow from the 
lower end of the rod and shell, and bolt the projector over the hole in the roof, 
using a gasket between the base and the roof to keep out water. The arrow- 
head on the base should point aft. When the projector is in place, the bow and 
handle can be replaced, and care should be taken to see that the handle points 
in the opposite direction from the beam of light ; for example, when the beam 
is thrown forward the handle should point aft. The studs and terminals are 
marked -|- and — . The operating mechanism of the rope control consists of two 
small drums which are connected to the operating drums on the projector by 
ropes. 

3. The E. C. projector, mounted upon a low truck, stands by itself under can- 
vas cover in a dry, dust-proof, sun-lighted room, from which it may be run out 
to any desired point within 1,000 feet of the switch board and dynamo, and is 
supplied by means of twin-core cable. The controller cable should permit the 
controller to be operated at 150 feet distance from the projector. The connec- 
tions and installation appear under head (F) page 97. 



SEARCH-LIGHT PROJECTORS. 



93 



(E) LAMP MECHANISM OF AEL PROJECTORS. 

1 Parts of lamp mechanism are as follows (fig. 124) : 

A negative carbon holder. -1/, fixed nut for focnsmg screw. 

b] positive carbon holder. ^\ stud of lamp switch for cutting out 
C, clamping screws for carbon clamps. feeding magnet. 

D vertical screw positive carbon clamp. O, ratchet and pawl. 

E horizontal screw positive carbon P, feeding magnet armature, 

clamp Q> contact of circuit breaker. 

F, negative carbon support. A*, adjusting screw for ratchet ann. 

G, positive carbon support. S, starting magnet. 

if. lamp frame. T feeding. . ^ ^ ,. . 

A', main lamp contact shoes. U, adjusting spring for feeding magnet. 

L, hand feed screw. 

2 Placing llir Uuiip in the drum.— The lamp may bo lifted by the top plate, 
but it should never be lifted by the carbon supports, as the strain duo to its 
weight is liable to spring them out of their correct position. The 18-inch and 
'M-inch projectors have obturators which prevent carboning the lamps before 
thev are placed in the drums. The drums of these projectors are, however, 
sufficiently large to readily permit adjustments of the carbons after the lamps 
are in place When inserting the 18-inch or 24-inch lamp in the di'um, the 




I2S. Obturator. 

shutters of the obturator should be opened and the arc magnet turne<l so that 
the opening is downward. This adjustment may be made after removing the 
pin on the side. Tlie lamp may now be placed in the projector, the arc magnet 
returned to its proper po-sition, and the shutter of the obturator closed. 

3 Carboning the lanip.—Tlw carbons are placed horizontally in the focal 
a.xis of the mirror. The positive carbon should have its crater toward the 
mirror. The projectors are intended for use on circuits of 1 10 volts, and a regu- 
lating rheostat is furnished with each jirojector to provide the necessary voltage 
at the lamp terminals. The rheostat is .shipped to conform with the voltage of 
the circuit, which should be stated when the projector is ordered. To obtain 
the best results, the rheostat should be adjusted once for all according to the 
volts and amperes given in the table at the head of this article. 



94 



HANDBOOK FOR ELECTRICIANS. 



The carbons must be of the best quality. Hardtmuth and Schmeltzer carbons 
are satisfactory. 

In placing the carbons in the lamp, separate the carbon holders as far as pos- 
sible by turning the feed screw. The larger, or positive carbon, should be 
placed m the clamp nearest the ratchet mechanism. Adjust the carbons so that 
they come in contact with each other exactly above the white line on top of the 
lamp. This line should coincide with the white line inside of the drum when 
the lamp is in place. The carbons should also be adjusted so that their axes 
coincide. Readjustment of the carbons is necessary from time to time so as to 
keep the crater in the center of the positive carbon and not allow it to burn 
off at the edge. If the crater becomes displaced on account of impurities in 
the carbons, the carbons should be readjusted so as to form a new crater in the 
correct position. 

4. Operating the lamp mechanism (figs. 126-7-8).— (o) After closing the main 
switch, the carbons will begin to feed toward each other until they touch and 
the circuit will be completed, so that the starting magnet will draw the carbons 
apart about \ inch, thus striking the arc. As the carbons burn away the arc 
becomes longer and the voltage across the arc increases. More current is thus 
compelled to pass through the feeding magnet in shunt with the arc. Its armature 
immediately breaks the circuit through the coil and then flies back, thus mov- 
ing the pawl and turning the ratchet at the end of the feed screw. 

START I NB MAGNET 



negative Garbori Can-ier 



Positive Carbon Carr-ier 




Coils ror the star-ting magnet of 24" lamps ar-e 

connected in nnultiple as shown 

Coils Tor 16.30 and 36 lanaps are connected in series. 



Contact Shoe 




FEEDING MAGNET 

Feeding magnet Circuit Breaker 



Sv>/itch to cut out 
reeding magnet 



126. Connections of 18, 24, 30 and 36 inch Automatic Projector Lamps. 

(?>) Focusing the la^np.— After starting the lamp, focus it with relation to 
the mirror by watching the rays. When the rays diverge, the arc is too near the 
mirror, and when tliey cross at some distance from the projector, the arc is too 
far from the mirror. Tlie proper distance between the' arc and mirror is 
obtained by moving the lamp backward and forward by means of the focusing 
screw. The light will not be satisfactory unless the lamp is in focus, and the 
operator must, therefore, never neglect to focus the lamp before using the 
projector. 

(c) When the arc is in the focus of the mirror the image of the carbons will 
fall on the ground glass of the vertical peep sight (see S, fig. 128a) so as to show 
the positive or larger carbon just touching the vertical line\ 

{d) In the 18-inch and 24-inch projectors the focusing screw is arranged to 
screw into the back of the lamp and is fastened permanently to the projector. 
The lamp should, therefore, be so placed that the thread of the focusing screw 
catches and draws the lamp into focus. 



SEARCH-LIGHT PROJECTORS. 



95 



(e) If the carbons are placed as described and the hum. Placed in the dinm hO 
that the two lines referred to iinder "Carbonmg the Lamp c.nncide, the arc 
Idn be so^iearly in focus that but little ad ustment will be necessar^•. 

n The lamp should be kept clean and free from carbon dust which occa- 
«i.m'i11v droDS from the carbons while burning. 

7r/ The fe?d screws may be oiled when necessary with a small amount of 
Jxl clock oTl but care should be taken to carefully wipe them after oi ing as 
ot l«-wi>^rsm a^ of carbon dust may adhere and cut the thread. The 

■Vrb m c-iiTia-es and parts carrying current should never l)e oiled 
■ rAs^iVw si g t clianges w^ in lamps construct^ed m different 

veirs 7ef ienle is made to tigs. 127-8. alike lettered, from which the plan ot oper- 
ation 'of all wall be readily understood. 




127. O. E. Search Light. 

The springs A take current from leads to the contact rings of the pedestal, 
the nath of the current being showni in tig. 128. ^ , . 

The car .ms are secured in clamps B on supports C the supports being mova- 
ble - des of the frame and controlled by screw-bars /> and i^. The larger 
claip'is for the positive carbon, in which the crater is formed and which will 
therefore be the farther clamp from the pr.i.iector mirror, i- is the autoinat c 
feed shunted from the lamp leads, having an electro-magnet^/, whit-h controls 
the an ture H, and which in turn operates the screw-bars D and £ through a 
imx^^mchet/-' and gearing J, when the voltage m the magnet is above M to 
5^ volts A- is the sei-ies-striking arc magnet which operates only when the cur- 
rent is much hi excess of thatre,piired for the lamp. A lug on its armature 
ImbnvcS the screw-bar D between two collars. The screw has a small iday at 
/: which is independent of the control of the automatic feed. Owing to the geai 
tile screw-bar D revolves but one-half as fast as E. E can also be turned by a 

^^SSS5 :^S^^rSt S^ The carbc^s are first ad^ust^ ^J^^-^h 
wrench to a separating distance of about half an inch Tlie automatic switcli 
3/s ould now lie closed. The main switch is closed next, and, as n.. current 
can pass mitil the carbons touch, the voltage across the carbons up to that 
moment must be 110 volts. The shunt magnet (called the teed) commences to 
' ibrate te voltage being greater than .^2 volts, and feeds the carbons together 
bv e uis f the Ki wl and the gear wheels of the screw bars. When the carbons 
touc a heavv momentary current passes (since the i;esistance is small and volt^ 
age at 110), the armature of the striking arc magnet is attracted, pushes back 



96 



HANDBOOK FOR ELECTRICIANS. 



the negative screw bar and forms ("strikes") the arc. The resistance of the 
rheostat, in circuit when first set np, causes a drop of 50 to 60 volts as soon as 
the current passes, and should be ad.iusted by the Ipver to the voltage necessary 
for running the lamp without flaming and hissing. The voltage recjuired in 
practice is usually from 45 to 49 volts; the feed will frequently operate at 50 
volts. The working current for the lami) varies with the size of the lamp and, 
incidentally, with the size of the carbons'; it is as great as 75 to 90 amperes for 
the 30 inch projectors, and from 25 to 35 amperes for the IS-inch type. 

There is often some flaming of the carbons which can not be controlled by the 
rheostat ; it is unimportant except from the fact that it decreases the intensity 

of the light; it will usiially disap- 
pear of itself. Horizontal lamps 
have a tendency to flame at the 
upper edge of the crater, thereby 
forming the crater on the upper 
edge of the positive carbon and dis- 
torting the reflection ; this tendency 
is corrected in some projectors by a 
horseshoe magnet, attached to the 
diaphragm in the projector, which 
draws down the arc by magnetic 
attraction. 

Some hissing will occur when 
starting up, especially with new 
carbons, and the lamp will not quiet 
down until a good crater has been 
formed in the positive carbon. This 
can be obviated by reaming oiit a 
crater in the ]30sitive carbon with a 
penknife before putting it in the 
clamp. 

Flaming and hissing are promoted 
by inferior carbons and are much 
increased if the carbons have ab- 
sorbed oil. Those now provided are 
of the Schmeltzer manufacture and 
are very homogeneous ; the positive 
carbon is usually bored axially and 
cored with a soft carbon, which 
materially assists in maintaining 
a good crater. Negative carbons 
are sometimes cored, but it is an 
open qxTestion whether this expe- 
dient does not conduce to the forma- 
tion of mushrooms. Carbons are 




128, 



Lamp Detaits Showing Method of 
Operation. 



packed in tins and should be kept covered in a dry place, as they readily absorb 
moisture. 

The momentary current of short circuit, when the carbons toiich, is ordinarily 
heavy and quite sufficient to throw the pointer of the ammeter clear across the 
scale and against the stops ; it need occasion no apprehension if it does not con- 
tinue ; if it does, the switch at the switch board should be quickly opened. This 
current may be as much as 50 per cent above the working current. 

Any abnormal current of the searchlight ammeter is usually traceable to 
either a mushroom on the negative carbon or careless handling of the socket 
wrench. In most cases of fusing of the contact plungers in the pedestal there 
is direct evidence of an attempt to regulate the feed by hand when the auto- 
matic gear is switched on. If the lamp does not feed, it is for the reason that 
there has been a burn out, or that the lamp itself is not clean, and in 90 per cent 
of the cases dirt is the caiise ; any attempt to remedy matters by use of a socket 
wrench, while the current is on, is (juite sure to short-circuit the lamp and pro- 
duce overload. 

The mushroom appears as a small protuberance on the end of a carbon and is 
of a pasty consistency. It can readily be removed by the end of a screw-driver. 
Ordinary attention to the working of a lamp should guard against its forma- 
tion. It will cause the carbons to adhere. 



SEARCH-LIGHT PROJECTORS. 



97 



(F) co]s:n~ectio?^s axd instantiation of u. s. electric 

CONTllOELED PROJECTOR. 






im 





128a. Parts of Projector and Controller. 



1. Parts of projector and controller are as follows: 



liiiiiil stiir wIutI for sltiw vcrtioil moveiiient. 
wlioi'I for tliiiiwiiiK out split nut usod forconiu'ct- 
iuK or (iisioiiMccting the drum from the base 
mechanism. 

wheel for slow horizontal movement, 
hanii star wheel for olampint; turntuhle to center 
pin for eleWrical control. 

wood handles on drum for moving drum by hand, 
liani) wheel for clampiu)^ hand star wheel .1 when 
electric control is used, 
controller switi-h. 
controller handle, 
rontroller fuse box. 

controller couplinj; for connecting cable from the 
projector, 
focusing screw 



It, 



socket for inserting wrench to operate lain]) switch 
useil for cutting out feeding magnet. 
, socket for inserting wrench when feeding by hand, 
door used for adjusting the carbons and for clean- 
ing the front door. 

door used when carbons are to be adjusted or 
changed, 
front door. 

door used when adjusting negative carbons or 
cleaning the mirror, 
horizontal peepsight.-!. 
vertical peepsights. 

sliding case to be opened when lainji mechanism 
is to be inspected, 
jirojector main switch, 
latches for fastening ba,se sheeting. 
, base sheeting. 



2. Projector with base sheeting removed (fig. 129). The numbers indicate 
the places for oiling: 

The worm 1 at the back of each motor; the two worm trays ought always 
to contain enough oil to allow the worm to bathe in it ; the horizontal worm 
wheel at 2 ; the vertical countershaft at 3 and the tread wheel at 4, by \inscrew- 
ing the plug and oiling through the hole while turning the turntable one com- 
plete revolution, .so as to distribute oil along the groove in the tread wheel ring; 
the internal parts of the mechanism are oiled at 5, filling the grooves around 
the center rods; tlie cros.shead at 6 and 7; the vertical training at 8, by loosening 
the clutch and putting the oil inside, and the truimions at 9. The controller is 
oiled at 10. Any extra oil must bo wii)ed off so as not to allow dust to stick to it. 

3. Connections of E. C. projector and controller are shown in fig. 130. 
1714—7 * 



98 



HANDBOOK FOR ELECTRICIANS. 




129. Training Mechanism Controller and Cable. 



4. Wiring diagrams. — Fig. 130 shows searchlight connections except switch- 
board and lamp mechanism; fig. 132. switchboard and the vertical training 
mechanism shifted in position for clearness, and fig. 131 all important connec- 
tions when both the horizontal A B and vertical ^4' B' training slides stand at 
their middle positions and neither motor runs. 

In the horizontal training mechanism (all figs.) ^ and B are separate, insu- 
lated, metal plates on one block which slide together to the right or left for a 
total distance equal to one-half the width of the plate according 'as the con- 
troller's handle attached to the block is turned right or left. ^4 loses contact 
with the left brush X as it first moves to the right, or with the right-hand 
brush Y as it first moves to the left, and with either motion it slides succes- 
sively into contact with the five insulated brass fingers which press against it 
and which are the terminals of rheostat coils. Resistance is thus thrown out 
and into the armature circuit of the motor which trains the projector horizon- 
tally. Plate B, always in contact with its middle brush N, moves with ^4 and, 
like it, loses contact with its left or right brush, 31 or O. 

In a similar manner, insulated plates A' andB', of the "vertical training" 
mechanism, lose and make contacts with their corresponding brushes by being 
moved up or down (fig. 130 alone shows right position) by means of the same 
controller handle as above. 

A', like ^4, slides in and out of contact, successively, with its five brass fingers, 
which thus throw rheostat coils out of and into the armature circuit of the 
motor which trains the projector in a vertical direction. 

The " controller switch " being closed, the shunt fields cl both motors are 
excited. Either motor is started by turning the controller handle right or left, 
up or dcwai, sufficiently to slide A B or A' B' away from their respective brushes 
on one side. If to the right in the horizontal training mechanism, the current 
flows through the "horizontal training" motor's armature in one direction; if 
to the left, in the opposite ^ direction — thus reversing the motor's motion. 



SEARCH-LIGHT PROJECTORS. 

Hor-izorrt^l TrainlniS Switch _ Vertical Trainir 



99 




-D-CB 



For Use in Assembling. 

Likewise for the vertical training mechanism and 
motor. While the slides ^4 B, A' B' are at the 
mid ])ositions shown, all rheostat coils are in the 
motor armatiires' cii'cuits which are short-circuited 
and can not therefore revolve. But when ^-1 B or 
A 7? is moved in either direction the short cir- 
cuit is opened and the coils are gi^adually cut out 
and the speed is increased. There are four ste^js 
and either motor has accordingly four different 
speeds. 

5. Install ivg. — For either hand or 
electric contr(d the current should be 
led directly from the switch hoard in 
the dynamo room to the double-pole 
switch inside the base of the projector, 
both conductors going through insu- 
lated holes in the base-idate of the projector. 
Facing the switch the positive pole is to the left, 
and the negative to the riglit. 

The dead resistance should l)e placed near the 
switchboard, and in circuit with the positive con- 
ductor. This method of connecting is essential 
on accoimt of connections to the motor for electric 
control. The size of the conductors varies with 
the .size of tlie projector used, and is determined 
l)y the amperes i)er circular mil allowed by specifi- 
cations. 

A third wire leading from the dynamo room to 
the projector base is connected at the po.sitive pro- 
jector switch on the switchboard, and at the other 
end to contact No. 3 on the connection board 
inside the base of the projector. The third ^^^re 



131. Q. E. Controller and Connec= 
tions with Training Mechanism. 



100 



HANDBOOK FOR ELECTRICIANS. 



is used in order to get full voltage at motor terminals. Its cross section 
will vary with the length of the circuit, but the total resistance must not measure 
more than .05 ohm. The negative conductor of the lamp circuit is used for the 
return, and is connected at tlae factory from contact No. 4 on connection board 
to the negative side of the main switch. Seven wires connect the contacts of 




the connection board inside the base of the projector and those of the controller 
receptacle. The contacts are numbered both on the connection board and on the 
receptacle, and should be connected accordingly. The controller receptacle 
should be placed within a radius of 20 feet of the controller. The required size 
of the seven conductors varies according to the length of the circuit. The 





_ 




ll 







SEARCH-LIGHT PROJECTORS. 



101 



following table gives the inaximuin allowable resistance for each ^^^re, and the 
size of wire for circuits of various lengths: 



Number of 
Conductor. 


Size of Wire, B. * S. Gauge. 


Maximum 

Resistance, 

Uhnis. 


50 Feet. 


100 Feet. 


150 Feet. 


1 
2 
3 
4 
5 
6 


14 
14 
11 
10 
14 
14 
14 


11 
11 

8 

14 
11 
11 


9 
9 
6 
5 
14 
9 
9 


.14 
.14 

.07 
.05 
.62 
.14 
.14 



The searchlight barrel should move with the controller handle as if this were 
fixed to the rear i)art of the barrel. The farther the controller handle is moved, 
right or left, up or down, the more rapidly the projector should travel. Small 
motion can be gotten by momentarily striking, by means of the handle, a finger 
of the training mechanism. 

(G) OPERATING THE E. C. SEARCH-IilGIIT PROJECTOR. 

1. The key to good search light operation and management is thorough cleanli- 
ness in all the parts and frequent opportunity f ( )r practice by those to be called upon. 

2. The mirror will spot or frost in time if not kept in a dry place. The action 
is hastened by damp and by the practice of exposing it to the rays of the sun 
while drying out the barrel. The life of a projector is shortened one-half from 
lack of care. 

3. Dust the M /\ ^ f- £ — ^ 

mirror surface ! 
gently with a soft 
duster — do not 
clean by rul )bing. 

4. Set the car- 
bons before oi)er- 
ation and permit 
no use of the 
wrench except in 
focusing ; there is 
rarely any occa- 
sion for its use on 
the screw bar 
after the lamp is 
in operation. 

5. Every pro- 
jector front 
should be fitted 
with an extra 
outside door 
made of perforated fiber for the protection of the front glasses. 

6. Diverging lenses are i)lano-convex in the horizontal plane only. The door 
is made in strips similar to that having the plain glass, each strip being a plano- 
convex lens. 

7. The paraliolic surface projector which is gradually replacing all other 
forms, lights up a distant object with greater briglitness and distinctness. 

8. The rheo.stat (fig. 134) mu.st be able to carry the full current and have 
sufficient resistance to cause a drop (C X A') of 30 Volts from an 80-volt supply, 
or (50 volts from a llO-volt supi)ly ; this includes an adjustable resistance for a 
range of 10 to 20 volts. 

9. While hot the reflector should not be moved nor its door opened. 

10. The two carbons should lie in a straight line, the positive and larger is the 
fartlier from tlie mirror; if new or deformed a crater .should be reamed out. 

11. Waterproof covers are always pro\ided for projector, controller and 
rheostat. 

12. Cable couplings are liable to give trouble from moisture in spite of the 
water-tight ga.skets. Use only two end couplings; splice and in.sulate all other 
joints; cover with painted canvas and kee]) them as dry as possible. 

13. Fu.sing may occur in the contact i)lungers of the pedestal whose office is to 
connect the contact rings of the base with the main contacts for the lamp. When 




■--D--- 



103 



HANDBOOK FOR ELECTRICIANS. 



this fusing takes place tlie pedestal becomes locked and can not revolve. It is 
commonly caused by the nonseparation of the carbons, either from failure of 
the mechanism or the adherence of the carbons due to the formation of a mush- 
room on the negative carbon. The remedy is to increase the contact area and 
to use greater care in operating. 

14. For signaling, projectors may be opqrated by hand to throw the beam 
against the sky right, left, or down ; or supplied with a Venetian shutter in front 
to make the one and two short flashes of the letters of the alphabet. 

15. A good line of sight makes 3" or more with the beam at the object. The 
blinding effect of the beam is small at 7° angle. 

16. On a clear, dark night, the 60-inch Schukert projector enables the naked eye 
near it to see a light object 30 feet high by 20 feet wide at 6 miles distance ; but if 
dark it can be seen at this distance only by the aid of a strong glass, becoming 
visible to the naked eye at 4 miles. The 36-inch parabolic mirror permits the 
light object above to be seen at 4 miles, but if dark, only by the aid of the glass. 

17. The generating set requires one electrician and assistant ; the projector, one 
electrician and attendant ; the cable, one attendant ; observers, each with a signal 
man if at a distance. The last-named carries a lantern darkened on the side 
toward t'ne enemy. The new observer sees little or nothing. To him objects 
appear unnatural at night. He has not even a mariner's experience, and he inno- 
cently reports the searchlight a failure, while the practiced observer will obtain 
good results. This one takes a position on either side of the beam and uses a 
field glass having the largest possible object lenses, low magnifying power, and 
no diaphragm. He forms some conception of the objective and notes all con- 
spicuous details in the vicinity. It is important to find near the objective one 
or more points which are fixed, light colored and known, such as a house, beacon 
or shore, in order to direct the beam upon it quickly and then upon the objective. 
Well defined shadows caused by impiirities in the atmosphere should not be 
taken for dark objects. Moonlight is a favorable circumstance. Mist or smoke, 
however thin, is unfavorable. Training and continued practice are indispensable. 

18. Degrees of illumination of projectors: 



Mirror. 


Distance in 

yards. 


Diameter of 

beam in 

yards. 


Diameter of 
spot in 
yards. 


Coefficient of 
transparency. 


Times illumina- 
tion of full moon 
at zenith. 


36" Spherical, C = lOd) 
amperes. j 

60" Spherical, C = ISo) 
amperes. j 

36" Parabolic, C = 130 

amperes. 
60" Parabolic, C = 150 

amperes. 


3, 300 

4,40(1 
5, .500 
3, 300 
4, 400 
5,500 
7, 000 

10, 000 


120 
160 
lltii 
10(1 
130 
165 

3(;o 

510 


90 
110 

141) 

100 
125 
300 

430 


0.8 

0.7 

0.66 

0.8 

0.7 

0. 66 

0.7 

.7 


40 

20 

100 • 
55 
33 
15 

20 



19. The projector, readily movable to any desired point within 1,000 feet of 
the generator, is placed wholly apart from the works, more than 100 feet from 
the nearest heavy gun, as near as practicable to the area to be watched, not 
higher than is sufficient to overcome the earth's curvature, and in such position 
that objects may not obstruct the beam. Before it is lighted in the enemy's 
presence, it should be elevated to guard against illuminating objects in its own 
vicinity. After it is in working order, the screen, if any, is removed and the 
beam is gradually depressed to the horizon while moving to the right and left in 
exploration. 

20. The probability of a 60-inch projector being hit while in operation at 
night by an expert marksman on land at a half mile distance is less than ts^- 
The danger to projectors from ship's fire from unstable mounts at the usual 
distance is therefore quite small. It will lessen the accuracy of the enemy's 
shots to extinguish the lamp occasionally or to move it quickly to some other 
point. The only special protection wliich can be given or will be required is the 
same as for all guns — a thick earth parapet reaching to the level of the lower 
side of the barrel. The l^irgest search light constructed has a mirror 6+ feet in 
diameter and an illuminating power of 3 X 10" candles. 

(H) TRANSPORTABLE SEARCH-LIGHT EQUJPMENT. 

Four sets (figs. 135-6) were ordered in the first preparations for the use of 
the army in Cuba but could not be delivered by the largest American electrical 
firm using all of its resources to complete them until four months after the 
necessity for them had passed. 




137. Keyboard for Night=Signal Set. 



X -GENERAL ELECTRIC COMPANY'S NIGHT=SIQNAL SETS 
AND TRUCK=LIQHT CONTROLLERS. 



(A) NIGHT-SIGNAL SETS. 

Night-signal sets inchide four parts, namely: keyboard, cable, lanterns, and 

^""i^^ujhoard -The keyboard consists of a dial and operating handle mounted 
^,^n^vater-S-ht box containing the mechanism for connecting he lamps m 
varL c^omWtions. 'xhe keyboard is illuminated by ^--^^^J^^^j'^^l^^^ 

e h conta ts"Sc^^^ eight semicircular plates. Each plate is inade 

up of insu aing sections ofliard rubber and metal sections ^^hu^h comie t xyth 
n laimiin one of the lanterns. Obviously, when one of the contacts of the i ot^at 
higS nU-Ss on an hinlating section, the circuit through the lanrp i. broken ; 
when on a metal section, the circuit is closed. Wlien the pointer is turnea to 




138. Mechanism of Keyboard. 

the position on the dial corresponding to the desired signal, some contacts rest 
on trSnibber sections and others on the metal tectums thus connoj^^^^^^^^^ 
"nto circuit a certain combination of lamps. The lamps are ^"^^^"^^^^^^ 
however, until the knife switch on the rotating stud is closed by swinging the 
knob of the handle dovni toward the operator. .x,^^„„h fwn line nhnrs 

2. Co«Hrcf,o».s-. -Current is supplied to the kfy^^f ^ f?v,f .lZro?entad^ 
one of which is connected to the central contact in ^^^^r^^V ^VV ; tntid V^^^^^ 
and the other, by means of a brush, to the knife sNvitch ;'" ^ . '' ^"^ "^^^'^^^^ 
Each semicircular plate is connected to a contact in the lantein c.iblt, jecepta 
de? into whidi a plug is fitted to establish connection with the lamps through 

*^Ti;ecable'is^made up of sixteen conductors. One end of/ach conductor is 
connec-ted to a lamp, and the other end to the P^'^^",;^' "^j J, ^^s m^^^ 
cle on the keyboard. Eight conductors run from the 'iK^^^ outside ^^'^J^^^^^; 
the plug to the eight lamps, and the other eight conductors fori he leUi 
from the lamps aiid are connected to the central contact of the plug. W hen 

(108) 



104 



HANDBOOK FOR ELECTRICIANS. 



lamps are lighted, the current flows as follows: From the generator to the line 
receptacle on the box, to the contact ring, to the switch, to the plunger con- 
tacts, to the semicircular plates, to the cable, to the lanterns, back to the cable, 
to the central contact of the receptacle on the box, to the line receptacle on the 
box, to the generator. 

The circuits are shown in detail in the accompanying diagram ( 140) . The plug 
and receptacle are made water-tight by means of a soft rubber gasket, and the 
sixteen cables from the plug pass through another gasket in the gland which 
makes a tight joint by compressing the soft rubber around them. 




139. Keyboard, Showing Attaching Plug and Receptacle. 

3. Lanterns and ladder. — Each of the four lanterns has two compartments, 
one with a red globe, and the other with a white globe. The wires pass through 
water-tight stuffing boxes in caps which screw on each end of the lantern with a 
gasket and support standard lamps and sockets. 

The ladder is made up of galvanized-iron wires with metal cross pieces from 
which the lanterns are swung. 

(B) OPERATION. 



After the ladder, lanterns, and keyboard are in place they may be connected 
as follows : 

Connections to the line should go to the two small outside receptacles on the 
back of the keyboard box, and the plug on the end of the lantern cable should be 
inserted in the receptacle between the line receptacles. This plug can be 
inserted only one way, as the receptacle has a jMn which must fit into a slot on 
the plug. After the plug is inserted, the nut D (see fig. 141) should be screwed 
up tightly so as to compress the soft rubber packing. The plug should never be 
taken from the receptacle when the current is on, as the sparking is apt to 
injvire the contacts, particularly the center one which carries the combined cur- 
rent for all the lamps. Therefore, before removing the plug see that the knob 
on the handle of the keyboard is in an npright position. To operate the key- 
board, the arm with the pointer can be swung over the dial to the combination 
required, and the knob depressed. The cam actuated by the knob will then 



XKiHT-SIGNAL SETS AND TRUCK-LIGHT CONTROLLERS. 



105 



engage with a slot so that the arm can not be moved, and will remain in this 
l)osition until the knob lias been raised again. This arrangement prevents the 
display of false signals. If pulsating lights are required they may be produced 
by means of the pulsator switch on the central shaft. It is a small lever which 




In9uIat,ion BfocK. 
Plunjer Contact. 

i— •■Pulsator Switch. 



Operating Switch, 

Contact Spring 
Conductor Rin^. 



SIGNAL BOX 

140. Diagram of Connections of Night-Signal Set. 

extingiiishes the lamps in the upper lantern when pushed to one side and lights 
them again when released. The lamp socket on the keyboard is provided with 
a switcli, and when not in lase the lamp should be extinguished to prevent 
excessive heating when the doors of the cover are closed. 




141. Receptacle— Plug. 

(C) REPAIRS. 

The sof-t-rubber packings used about the couplings and cables should be fre- 
quently examined and renewed from time to time, as the rubber becomes hard 
and ])artially vulcanized ])y the long continued compression and heat from the 
metal, which ])ecomes cpaite hot when in the sun, especially in troincal climates. 
When worn out the cables can be replaced, one conductor at a time or all at 
once. To replace one conductor, unscrew the cap at the lantern and disconnect 



106 



HANDBOOK FOR ELECTRICIANS. 



the conductor from the lamp and pull the cable out after loosening the pack- 
ing in the gland. Cut the seizing about the cable and separate the defective 
conductor as far as the cable plug on the box and cut away the canvas jacket. 
With the plug removed from the receptacle, unscrew part A and slip it up 
the cable some distance, then unscrew part B after taking out set screw C, and 
work the gasket back on the cables so that B and E can be separated. Pull 
B and E apart and disconnect the defective conductor from the contact and 
pull it out through the gasket. Unsolder the terminal on the conductor, and 
solder it to a new conductor ; pass the new condiictor through A, through the 
gasket, and then through B, and connect it to the contact. Screw B in place, 
and after replacing the set screw, push the soft rubber gasket down into the 
gland. As there are sixteen conductors, the rubber gasket is not easily inserted, 
but by pulling on one conductor at a time and changing about, the gasket can 
be worked into place, and then part A can be screwed iip and a new canvas jacket 
put on. 

To connect the other end of the conductor to the lamp in the lantern, pass it 
through the rubber gasket in the gland and connect it to the lamp socket. 
Screw up the gasket in the gland tightly, replace the cap on the lantern and 
screw it down hard. When repairing the cable in this manner a good oppor- 
tunity is offered to ijut in entirely new gaskets all around. The method of pro- 
cedure in removing the entire cable is, of course, the same as in removing one 
strand. The cable should be painted occasionally with some tar compound as a 
preservative, in the same manner as standing rigging. 

(D) STANDARD OUTFIT. 

The coraplete United States Government signal outfit includes : 1 keyboard, com- 
plete with cover and lamp ; 1 ladder and cable with male half of coupling ; 1 reel of 
extra single condiictor cable ; 5 lanterns (4 for ladder and a spare lantern) ; 10 32- 
candlepower, 110-volt lamps; 1 16-candlepower, 80-volt lamp for keyboard; 1 
tool box containing the following — 2 fork wrenches. 1 spanner, 1 grip for male 
plug and shell, 10 spare gaskets for lantern glands, 1 spare gasket for coupling 
of 16 conductor cables, 2 spare gaskets for main line plug contacts on keyboard, 
2 spare washers for main line plug contacts on keyboard, 10 spare washers for 
lantern cap, 1 spare washer for coupling, 16 spare coi^per terminals. 



TRUCK-LIGHT CONTROLLERS. 




'42. Diagram of Connections of Truck=Light Controller. 

The controlling- switch for truck lights is contained in a metal box and con- 
nected to the ciic lit by leads passing through the hollow pedestal on which the 
box is mounted. The handle on top of the box is used for operating the switch, 



NIGHT-SIGNAL SETS AND TRUCK-LIGHT CONTROLLERS. 107 

and tho lamp lighted at any one position is indicated by the pointer. The light 
may be pulsated by moving tlie pnlsator Initton on the side of the box in and out. 

When connecting the truck-light controlling switches follow the diagram in 
fig. 142. The terminals on the inside of the box are marked ^f R, M IT, F B, 
F ir,- those to which the line connections are made are marked L. 

Tlie line -wires should be connected to the terminals marked L: those from the 
' ' main " red half of the lantern to M li; from ' ' main " white to M W; from ' ' fore " 
red to F li, and from "fore" white to F W. 

Termin ds are provided which should be soldered to the ends of the wires and 
fastened to the contacts ^^nth screws. 

The covers on the sides of the box should be removed every three months. If 
the contacts are discolored they should be polished, and any irregularities or 
Iburnt places should be smoothed off ^vith a file. 

(F) DIRECTIONS FOR THE BOUGIITOX XIGIIT-SIGNAI. SET. 

It is transported in three boxes — keyboard, cable, lanterns. 

TO ASSEMBLE. 

1. Open box No. 1 and remove keyboard and secure its base at place where it 
is to stand by suitable screws or bolts. 

3. Open box No. 2 and take out lantern support and lay same along the 
ground with its upper end (shown by absence of electric cable which depends 
from the lower end) near the foot of staff from which it is to hang. 

3. Connect the electric cable which depends from the lower end of the wire 
cable lantern support to the keyboard, by its coupling, and screw the collar 
home. Connect keyboard with electric current of emplacement, through the 
two binding posts seen on tender surface of keyboard. Wires should be equal 
to serve sixteen 10 candlepower lamps at once. 

4. Uni)ack box No. 8 and take out glass lenses for lanterns, four red and four 
white, carefully dust and ^^'ipe same with clean cloth, and place same in frames 
thus making four doable lanterns of white and red lenses, white above and red 
below. 

The lantern frames are made ready for lenses by unscrewing the top and bot- 
tom nuts of the four side bolts which make the lantern frame, when the top or 
bottom sockets may be moved up or down ready for the lens. 

The mid-division of the lantern carries the electric lamp sockets, and sustains 
the weight of the double lantern ; it is clutched and bolted to the larger wire 
cable and is not to be moved. 

Rubber gaskets are placed between each end of each lens and its support, 
making the lantemi gas and water tight. 

5. Wipe electric lamps with clean cloth, pu.sh lamps to mid-division of lantern, 
three on top and four on bottom. Lanterns are opened for setting lamps in 
place by unscrewing top and bottom caps. Replace lantern ends by screwing 
same home. 

Test electric connections of each lamp of each lantern from keyboard. See 
that each lamp lights promptly, and gives its light in full candle ])ower. 
Lamps failing to light fully are broken or not set right in socket, and must be 
replaced or properly placed in socket. 

ti. Hoist lantern frame to place on mast and make fast to outrigger, back stay 
aud below. 

7. Place pilot light in its socket at back of keyboard. 

TO USE. 

The keyboard swings on the base in an arc of 180^ in order that the operator 
may face the point signaled. 

To swing the keyboard, pull the stud at the side of iipper part of base and 
swing the keyboard in the direction desired. The swinging device is self-lock- 
ing at various intermediate points of its arc, by means of the stud above 
mentioned 

The telephotos shows the signals, letters or numerals shown on the top of the 
keys of the keyboard as a flash signal or as a standing signal at the will of the 
operator. 

To signal by flash signal, press down the jiroper letters or numerals and hold 
same do%vn, five, eight or ten seconds, according to the ability of the person 



lOS HANDBOOK FOR ELECTRICIANS. 

signaled to read signals ; upon releasing the key, the signal disappears and you 
are ready to show the next. But one signal key may be used at once, to avoid 
confusing the receiver of the signal. 

The pulsator may be used at any time with any signal. 

To make a standing signal, press down the proper key as before and give the 
key a twist to the left and it will stay down. As long as the key is down its 
letter or signal is shown. To release the- key, give the same a twist back and it 
will rise to the level of the others, and its signal will disappear. 

Before sending important messages one should be familiar with the keys, 
learn what letter or numeral they represent, learn the pressure needed to bring 
down a key, the time required for a signal to appear, be read and to disappear, 
learn the use of the pulsator, and the interval. 

To examine the contents of the keyboard, unscrew brass studs around outer 
margin of key plate, when key plate may be lifted out of place and all contents 
of keyboiird will be in plain reach and sight and so simple as to require no 
explanation. In replacing key plate see that its rubber gasket is in place. 

When not in use, the door in brass cover of keyboard should be pulled dovni, 
and the telephotos protected by a canvas cover. 

The keyboard being hermetically sealed, might in some climates show signs 
of condensation on account of temperature in the box and that on outside not 
being equal. Should this ever occur, remove the keyboard plate and take small 
cork in bottom of box out. This will make temperature inside and outside 
alike. 



XI.— MISCELLANEOUS APPARATUS. 



(A) THE FIRIXG KEY. 

The firin-^' key is a suiall, single-throw knife switch with spring to keep the 
knife nonnally open, with an ebonite turn-buckle over the jaw for increased 
safety and with a brass i)in to hold the knife locked in the javs when desired. 

(13) THE ELECTRIC FUSE. 

Tlie electric fuse offers the safest, simplest, cheapest and most effective means 
of firing high explosives or large charges of i)Owder, and the only means of 
igniting separate charges simultaneously for greater destructiveness 
or a snigle'charge from a distant point, or at a required moment, or 
under water. 

I. — It c-onsists of about i-inch length of fine wire of platinum- 
iridium alloy. O.OOl to 0.003 inch diameter, } ohm to 1 ohm resi-stance 
cold, called "the bridge wliich is surrounded by a little gun cotton; 
next t') this is placed fine gunpowder for igniting a powder charge 
or mercuric fulminate for detonating high explosives. The whole 
is fixed within a copper case. An electric current of specified 
strength reddens the bridge, ignites the gun cotton and fires tlie fuse. 
1. The commerc-ial fuse (fig. 143 is actual size) has a copper shell 
A with corrugation to hold more firmly the sulphur cement F 
which seals up tlie open end and holds firndy in place the fuse wires. 
B is the chamber containing 20 to 50 grains of fulminate. A little 
gun cotton surrounds the bridge which is soldered to the bared ends 
of the fuse wires J). The wires, 4 to 40 feet long, 
have cott(in cover soaked in asphalt for ordinary 
oiitdt)or work and gutta-percha covering for sub- 
marine work. 

2. The United States Navy electric fuse (fig. 
144) has the copper case in two parts which screw 
together, ^',.-inch. The upper or inside part holds 
S.") grains of the fulminate. The h)wer, open at 
both ends, is filled with sulphur and glass, which 
holds fixed in place the wire ends and bridge. 
When the fulminate is dry, the spaces in both 
parts are filled with dry pulverulent gun cotton 
and the parts are screwed together. 

3. The mine fuse (fig. li-i), without the copper 
case and fitlminate may be u.sed in ordinary work 
to fire gunpowder. To detonate explosives, attach the cop- 
per case containing mercuric fulminate which varies in quan- 
tity with the kind and size of the charge. 

Plug A' has two opposite longitudinal g^-ooves in which the 
lead wires C C, covered witli paraffined cotton braid, are 
buried. A cut round the middle allows the two leads to cross 
half over, so that each lead leaves the plug in the opposite 
groove from that which it entered, thus holding the wires 
fast. The ca]) B fits tightly over K and is glued to it in a 
solid piece. The copper case slips over the whole and is held 
bv dents near the end. 

4. The gun fuse (fig. 146) has a bra.ss case a threaded on 
the exterior to screw into tlie axial vent of the breechblock to 

Its rear iiart is scjuared f(^r a wrench. The interior is thinned at h 



143. 



144. 

A, IiiwcT tube; J?, up- 
per tulu-; (.', pliiK of sul- 
phur iinil kIiism: />, 
briiiKO It'KB: /■', liriil^ri-; 
l\ Kun otitton; (.'. ful- 
niiniitv: U, fu«o wires. 



the shoulder. . 

for a gas check. A hard rubber plug, ./", holding in a fixed position the leads to 
the bridge, is seated at c. Small-arms powder surrounds the bridge and gun 

(109) 



110 



HANDBOOK FOR ELECTRICIAXS. 



145. Mine Fuse. 



*''***' ' ^,^v ^^ols of the priming disc and lash the wire to the disc which is 
incii -D placed centrally in the charge. If the latter is very large, two 



/h 



cotton. The escape of gas outside the fuse is prevented by the expansion of the 
thin part at b, and inside the f nse by the hard rubber being driven into the 
enlargement of the wire duct. 

II. — The electrical tests of a fuse are for — 
\/o 1. Conductor resistance cold (bridge and short leads), 0.3 to 

Y 1 ohm. 

y 2. Conductor resistance hot just before ignition, 0.45to2ohms. 

^jLjrr^ 3. Insulation resistance between conductor and case, 1 meg- 

ohm. 
4. Strength of current required to fire, 0.3 to 0.8 ampere. 
The testing current ought not to exceed one-tenth of that 
necessary to fire. 
III. — Placing the fuse in a mine charge — 

1. If of gunpowder, fill the bag one-third full, piit the fuse, 
or two fuses in parallel, on top, fill up the bag, leaving 6 inches 
slack in the wires, and lash tightly the mouth of the bag and 
wires. If the bag is vulcanized india rubber for service under 
water, the mouth is well smeared Avith india riibber solution 
and closed between two hard-wood clamps bolted together. 
Tension on the fuse is prevented by a stout string from the 
clamp hitched to a point on the fuse wires. 

2. If the charge is gim cotton, insert the detonator in the 

A , copper ■ 
hollow wood < 
wires, 0.035 .„..., „, ., ..-.,. ,-.,.., - - , .^„ 

bridge, 0.0025 inch ; F, or three priming discs, each with its detonator, are used. It 
priming ; H, fulminate the charge is wet guii cottou the primer must be dry and 

held by drop of coiio- 3. In a dynamite or gelatine cartridge ( 147), punch with a hard- 
dion ; A', plug of beech- wood pill a liole ill the lower end or middle, 1 inch longer than 
^'°'"'' the detonator and without removing the paper cover. Press 

ft , the cartridge to close the 

_A_A^wvv\J I .'^ mouth of the hole after 

insertion, and lash with 
string the wires along the 

-r^ — r — VAAAA/^'Tr ' ^€ Cartridge. Half hitches or 

ft */* ^"^ _ other tying of the wires 

*'*^- may cause short circuits. 

IV. — To fire u-ith a battery. — See that all persons are distant or protected; 
attach the leads ; close the switch firmly ; detach the leads. 

Before using the battery ascertain from its constants and external resistance 
if it can supply the necessary current strength to each fuse. In no case can this 
be less than the current given for ignition, nor be more than 25 per cent in 
excess. If the fuses are two in parallel, instead of all being in 
series, double the current will be required. 

V. — To fire with the service dynamo. — 1. If no one is near 
the mine or gun, connect the leads to the posts ; seize the handle 
with one hand ; steady the box with the other ; lift the ratchet-bar 
to its full length, then press it down quickly with constant 
force until the bar strikes the bottom with a thud, when the 
fuses will be fired ; detach the wires. Churning the bar up and 
down to fire is useless and harmful. 

When there are three binding posts on the box(fig. 148) and 
the number of fuses is small, join the leads to the middle and 
either outside post; when the number of fuses is large, join the 
the main leads to the outside posts and run a third lead from 
the middle post to a point midway of the fuses in series. 

2. In case of failure to fire when the number of fuses does not 
exceed the capacity of the battery or dynamo, there is probably 
a break, a poor joint or a contact between the two leads. The 
leads being detached, go over the whole circuit, lifting up the 
wire in search of a break inside the insulation, examining the joints and watch- 
ing for contacts. If this fails to reveal the open circuit, locate it by use of a 
single high resistance cell and the fine wire coil of the detector or other Galv. of 
sufficient resistance to keep the testing current below ^^y ampere. 

3. If trouble is suspected in the dynamo, try a fuse through a resistance ; or, if 
after removing the endboards, a spark is seen at the short-circuiting key when 
the bar strikes it, the dynamo is in order. The resistance between the two bind- 
ing posts should be zero when the bar is up and about 6 ohms when pressed 




S^ 



.Jl 



147. 



MISCELLANEOUS APPARATUS. 



Ill 



dowTi hard. When there are three posts and the bar is np, the R between the 
left-hand and middle ones, looking at them from their side of the box is 0, and 
between the middle ami ri.i,dit ones, infinity. 

VI. — Precautions in firing fuses are as follows: 

The last thing done around a mine or a gun is the joining 
of the fiise wires to the leads. 

At the battery or dynamo just before firing, attach the 
leads to the i)osts. 

Place battery or djniamo in a safe place and as near the 
mine as safety i)ermits. 

A rough test of the generator just before firing can be 
made by its bringing for an instant to a barely perceptible 
red, a certain lengtli of platinum fuse ^vire; or by firing a 
single fuse through a given resistance. 

The service dynamo will fire a very few fuses joined two 
in ])arallel. 

In jointing, scrape clean the ends, wind closely, solder 
if convenient, with resin for the ttux, and in all cases wrap 
the joint with tai)e. 

Fuses must bo kept in a dry place i-emote from explosive 
or strong acid, and should be tested before using. 

Fuses varying 10 per cent or more from their specified 
•resistance are rejected. 

Put detonators under test in a safety box ; never turn a 
detonator toward a person. 

A detonator must on no account be bent, struck, heated 
or rouglily handled. 

Avoid strain on a fuse by hitching a tension string from 
the charge case to the fuse wires. 

For certainty of ignition of a single important charge, 
two fuses are connected in parallel. 

Always use fuses of the same kind in a circuit. Lead 
^vires have double the diameter of fuse wires. 

Cxuard a.gainst injury to insulation in tamping, and bare 
wire at a joint or other i)oint in the circuit. 




148, 



30'Fuse Firing 
Dynamo. 



(C) EliECTRIC BELIES. 



,^., 



,-?-- 



1. Electric bells are of two kinds — single stroke (fig. 149) and vibrating. 

In the vibrating bell (fig. !.")()), the armature is held by a spring, (', against 7?, 

adjustable at D. The key A' being closed, a current fiows. through L, P, B, F, C, 

E, P , K and L. attracting the armature, striking the 

gong and breaking the circuit at B. As no current 

; now flows, the sjtring at C throws the armature back 

ci against B, reestablishing the current which acts as 

i before. Both contact points, B and F, are of platinum 

i to i)revent corrosion by the spark. 

2. Trouble in beircircuits is usually due to dirty 
contacts at B and /', or to some part of the circiiit 
touching the metal frame or to a break in the circuit, 
usually at a __ 

b i n d i n g 
l»ost, key t>r 
joint. Use 
insiilat ed 

wire only; ,., ,5-. 

fasten wires 

under composition staples without ben<ling the wire; keep i)arallel wires one- 
half inch ai)art . never run two wires under the same staple or through the same 
hole; solder splices, and cover with insulation. 

To ring two or nicr bells, each with its owni button, by means of one battery, 
see fig. 151. 
To ring one bell with one battery from two or more buttons, see fig. 152. 




d9_J 




112 



HANDBOOK FOR ELECTRICIANS. 



(D) THE AlVEMOMETER (FIG. 153). 

The anemometer measures the velocity of the wind in miles per hour. 

1. It shoiild be placed on top of a telegraph pole or other support without 
vibration, erected on the highest site in the vicinity. Any obstruction within 
500 feet of the site and 10° or more above it is objectionable, as the velocity of 
the wind is diminished by friction from 20 to 50 per cent within 100 feet above 
the ground. Two wires run fi'om it to the distant register. 

2. Four brass cups, C, on the ends of arms, in a wind, turn a vertical shaft, 
A, whose screw thread, B, is geared into wheel, D. Two D-shaped lugs on the 
wheel are arranged as shown to close momentarily an electric circuit every 25 
revolutions on a single-stroke bell, every 500 revoliTtions on a self -register, and 
permanently during 25 revolutions on the stop clock. The wheel must be spe- 
cially constructed for each of the above registers ; for the stop clock the two 

D-lugs are replaced by a semicircular ridge join- 
ing their positions, which then closes the circuit 
during one-half revolution of the wheel. 

3. To get roughly the velocity of the wind in 
miles per hour with the single-stroke bell, connect 
up anemometer, bell, and battery, as in fig. 153. 
Note by means of the secondhand of an ordinary 
watch the number of seconds between two con- 
secutive strokes. Divide 180 by that number. 

Example. — The seconds hand stood at 32 when 
the anemometer rung the bell and at 47 at the 
next stroke. Required, the velocity. Interval = 
15 seconds; 180 h- 15 = 12 miles an hour, approx- 
imate. 

4. Anderson's stoj) clock performs the above 
aiitomatically and more accurately, its electro- 
magnet taking the place of the bell's magnet in 
fig. 153. Its single second's hand moves over a dial 

^ D ?S M &-'i ^I'l'^'i^o two scales — the inner one representing in 

jK Wio ^ S" ' '^ ^^^^ usual way seconds to a total of 60, the other 

^ ^^^ •^'' " scale of iinequal parts, velocities in miles per hour. 

Experience shows that the velocities are a little 

greater than those given by the above rule. 

By means of a lever and cam, the seconds hand 
can be brought to the vertical or position from 
any other on the dial. A very light spring on the 
movable end of the armature bears normally 
against the balance wheel and thus keeps the clock from running ; when the 
magnet is energized from the anemometer, the armature both releases and starts 
the balance wheel, and the clock runs while the cups make 25 revolutions, or 
the air, 2V i^^^il© ; the armature then released stops the clock. 

To operate: Close the circuit; bring the hand to 0; if it then starts, the 
anemometer has closed the circuit and it will be necessary to wait until the hand 
stops, when reset it at 0. In a few moments it will automatically start and later 
stop and register. 

5. Gibbon's self -register (fig. 154) has an electro-magnet in the place of the 
bell's magnet of fig. 153, and a 4-inch diameter drum revolved uniformly and 
translated longitudinally by clockwork so that the point of a fixed pencil will 
describe a spiral upon a sheet of paper laid upon the drum's surface. The 
pencil is held at the movable end of the magnet's armature. The paper is ruled 
parallel with the drum's axis into five minute spaces. 

Whenever the anemometer, after the connections are complete, makes about 
500 revolutions, corresponding to points moving with the wind exactly 1 mile 
apart, it closes the circuit and the pencil makes a sharp dent in the spiral. 

To put the sheet on the drum, place the cylinder S on a table wnth the screw 
rto the left-hand; place the paper on the cylinder with the top of it from the 
screw. Let the line marked 12 noon come on the line of the cylinder, and place 
a rubber band on each end. The lines at each end of the paper will then exactly 
coincide. Place the cylinder S in its position, so that the end opposite to the 
screw T will be near the post on which it rests. Slide the small sliding bar on 
the horizontal bars O O until it fits on the ends of the screw-axle T; then 
revolve the cylinder until the pencil rests on the end of the upper line marked 
12 noon, or the line corresponding to the hour at which the instrument is set, 
and tighten the thumbscrew N. 





153. Anemometer. 



MISCELLANEOUS APPARATUS. 



113 



To obtain the velocity from the self-register take the number of spaces and 
parts of spaces between the mile marks i-ecordecl in the five minutes preceding 
the time of observation and multiply the result by twelve. 




TO ANEMOMETER,^ 



FROM ANEMOMETER 



154. 



Ex: Suppose the number of spaces indicating mile marks between 8.55 and 
9 a. m. were 1^-; then the velocity of the wind is 1^^ x 12 = 15 miles per hoiir. 
When the velocity is less than twelve miles per hour the velocity wnll be 
determined as follows: If the interval between the last two mile marks is 7 
minutes, tlien the current hourly velocity will be obtained by dividing 60 by 
7=8^ miles. 

6. The velocity of the wind may be roughly estimated without anemometer: 



Xiimc. 


Miles 
per Hour. 


.\lipiirHiit Kflect. 


Calm 




1 to 2 


No visible horizontal motion to inanimate matter. 


Light 


Gentle 


3 to 6 Moves li'iivfs of trpfs. 

6 to 14 Moves small liranches of trees nnil blows up diiat. 

15 to 24 i Gooil Kiiiling breeze, and niaki-s wliite caps. 

25 to 29 1 Sways trees and breaks siiiall branches. 

40 to 59 1 Dangerous for sailing vessels. 


Fresh 


Brisk 


HiKh 


Gale - 


Storm 


Hurricane 


80 or more 


Prostrates everything. 



To find the pressure of the wind in pounds upon a surface exposed perpen- 
dictilariy to the wind, multiply together, 0.005, the surface in .scpiare feet, and 
the .s([uare of the velocity of the wind in miles per hour. Or, P = 0.005 S\'-. 

7. Care of Aiioiionich'r. — Keep mechanism clean and bearing parts oiled with 
clock oil. The anemometer should be compared every season and found to 
agree with at least two others supposed to be in good order. 
1714— « 



XII.— PRIMARY BATTERIES. 



(A) GENERAL BIRECTIOKS. 

1. When any two different metals are partially immersed witliont touching 
in a liquid which acts more upon one than the other, the combination forms an 
electric cell ; if a wire joins the metals outside the liquid, a current of electricity 
will flow around the circuit thus formed. Zinc is usually one of the metals or 
plates ; copper or carbon is the other and its upper part is the positive pole of the 
cell. Sometimes two liquids are iised — each around its own plate — and kept 
separate by a porous diaphragm or by gravity. 

2. The current from an electric cell diminishes after a time more or less rapidly, 
due chiefly to three causes: (1) impurities in commercial zinc, causing local 
action ; (2) the production of new and hurtfvil compounds in the cell ; and (8) polar- 
ization, or the formation on the copper or negative surface of hydrogen gas which 
not only increases the resistance of the cell liut tends to make the poles alike. 

(1) Local action is remedied by coating the zinc surface with 
" y ' '• 'ii '» ™6rcury, a process called amalgamation; (2) hurtful compounds 
v'-lCJiyJiiLv'-iix^ are removed from time to time : (3) polarization is partially or 
t + (,/■ i/^'^' '^^lolly checked by enlarging and roughening the surface of the 
po e I- ' negative plate, or, preferably, by surrounding it with an oxide or 
other substance, termed a depolarizer, which takes up the hydro- 
gen as it forms. 

3. Management. — (a) In mounting, see that all the parts are 
clean, the bearing surfaces of connections brightened and the 
connections made tight by using English binding posts, or doub- 
ling the wire througli holes too large, so as to fit. Use only rain 
water and the best materials. Do not spill liquid or salt over 
155. Typical, parts to remain dry. The two plates of a cell should not touch, 
nor any two cells of a battery. Cells of different kinds are never joined in the 
same battery. 

(5) For proper maintenance all cells should have covers to prevent evapora- 
tion, all zincs in acids should be amalgamated to prevent local action, and rims 
of jars should be dipped about an inch in melted paraffine to prevent salts from 
creeping over. Keep cells well insulated on porcelain holders or paraffined wood 
in a dry, cool and clean place, esi^ecially free from dust and change of tempera- 
tu.re. The cells are preferably arranged in single rows on shelves accessible 
on both sides and having a hood to carry off the gases. Direct sunlight on 
glass jars may crack them. 

The battery room, dry, light, ventilated, and with cement floor, should have a 
sink with entrance and exit water pipes, and such facilities as spare jars, pitcher, 
scales, brushes, syringe, hydrometer, funnels, graduated glass and mercury 
dish. All trace of grease or soap must be excluded. 

(c) After dismounting, all battery parts are cleaned while wet. Scrape off old 
salt and crust, and rub with a brush until a bright surface appears. If plates 
are greasy, soak in strong soda solution. Carbon plates and porous cups are 
soaked in water several hours. Re-amalgamate the zincs. File or rub with 
emery the connections, and finally dry, reparaflBne and repaint with asphaltum. 
Varnish the tops of plates. 

4. Amalgamating zincs. — First clean the zincs, then dip in sulphuric acid 
solution (jL), or any old acid solution, about one minute. Then transfer it to an 
open shallow dish of iron or ijorcelain whose bottom is covered with mercury 
and a little of the solution. While turning the zinc over so that every part 
comes into the mercury, rub the surface with a swab made by winding cloth 
around the end of a stick. 

Or, mix, by weight, 1 part nitric and 2 parts hydrochloric (muriatic) acid and 
add slowly i part mercury. When dissolved add 3 parts more of hydrochloric 
acid and stir. Clean the zinc with potash and water; immerse in the above 
solution for a few seconds. Rinse in clear water and rub with battery brush. 

5. Solutions are mixed in large jars to obtain utiiformity by pouring in first 
rain or pure water, and adding the acid slowly while stirring. Let the mixture 
cool and settle and do not use the sediment. 

(114) 



PRIMARY BATTERIES. 



115 




156. Sampson. 



6. The desirable qualities of a cell are (1) a large and constant E, (2) a small 
and constant R, (3) cheapness of materials, (4) no waste of materials when not 
giving a current, (5) easily inspected, (6) easily refreshed, (7) no offensive 
fumes, (8) first cost small. No one cell has all of them. 

7. Several cells of the same kind and size may he united in series, parallel or 
both, to form a battery. Tlie two forms of battery are the primary and 
secondary. There are five different kinds of primary in general use — Leclanche, 
dry, gi-avity, copper oxide, and bichromate. 

(B) speciatj directions. 

(fl) Leclanche Cell (Fig. 156) 

1. A zinc rod, or cylinder, and a carbon cup containing a mixtiire of nearly 
equal amounts of broken carbon and manganese bioxide stand in a saturated 
solution of sal ammoniac. £"=; about 1.48 volts; R of 5 

by 7 inch cell with zinc rod is aboiit 1 ohm. 

2. The Leclanche furnishes a strong current for a short 
time, but it soon begins to polarize. Left on an open circuit, 
it regains its strength without the con.sumption of material. 
It is useful for intermittent work only. 

3. 3Ioiintiiig. — Fill the jar about one-third full of water and 
stir in about 4 ounces of sal ammoniac, so that there may not 
remain an excess of the white salt. Put in the two plates 
with cover. Liquid is about 2 inches from the top. If 
l)orous cup, let the cell stand twelve hours before losing ; or 
l)etter, fill the cu]) with solution through the gas hole in the 
seal. If i)risms, tliey are held tight against the carbon by 
two strong rubber bands. 

4. MaiiiteiKuicc. Add water as it evaporates and a little 
salt as the current gets weak. Wipe off the first trace of 
white salt forming on the tops of parts due to carelessness in setting up the 
cell. Hard scale on ])lates shows that the solution is too strong. 

Never leave the cell on closed circuit and for safety detach both poles when 
the cell is not re<iuired. If a Leclanche fails, examine the connections, or add 
a little salt, or replace the solution witli new. or soak carbons in hot water for 
three hours, or scrape off the hard scale, or fill carbon cup with fresh mixture, 
or throw away all except the jar. 

A green salt f ortning on a binding post is cleaned and the metal part is recoated 
with asphalt. One carbon outlasts three zincs; one zinc rod gives 3U to 40 
ampere hours. 

(h) The Dry Cell (Fig. 157) 

Belongs to the Leclanche class. A zinc can enveloped in pasteboard, and 
always having a sealed cover, serves both as jar and i)late. 

1. The central cylinder of carbon and manganese oxide 
is surrounded by an absorbent or gelatinous body well soaked 
in an excitin.g solution of 1 part (by weight) sal ammoniac, 
1 i)art Zn. chloride, 3 parts plaster, 2 parts water. The 
ingredients are often kept secret. 

2. E=i.'i volts, and R = about 1 ohm for a "i-inch cell. 
Its ampere hours is less than for a licjuid Leclanche. But 
it is cheap, portable, may be laid in any po.sition, <ind kept 
for a long time if not overworked and if the inside moisture 
does not escai)e. A good dry cell may ring a door call bell 
eighteen months. 

3. If it fails, bore a small hole in the seal and inject 
water. If its strength is regained, seal up the hole tightly ; 
otherwise throw the cell away. 

(c) Gravity Cell (Fig. 158). 

1 . A zinc plate, Z, stands in a solution of zinc sulphate, 
and a copper plate, (', in a soluti<m of copper suljihate 
(bluestone), the coi)]ier being at the bottom. E = about 1.08 
■ 157. Dry Cell. volts. R o( a Q by S inch cell in good condition is about 3 
olims. The gravity gives a steady current in a closed cir- 
cuit and is employed for continuous work only. Good forms are Crowfoot 
and Eagle. 




116 



HANDBOOK FOR ELECTRICIANS. 




2. Mounting. — Unfold the leaves of the crowfoot copi^er so as to form a cross, 
place it in the bottom, bring its wire up straight and bend it sharply over the 
edge for a clamp. Drop in crystals of copper sulphate, about three pounds, to 
the top of the leaves. Pour in rain or soft water until it covers the zinc, put on 
the cover and short-circuit for two or three days. If 
wanted sooner, let the water come to within an inch of the 
zinc and then pour carefully on top a solution of 3 ounces 
of zinc sulphate in svifficient water to cover the zinc, or 
zinc solution from an old jar, if clear, or a little sulphuric 
acid. 

3. Maintenance. — The cell is in good condition when the 
lower copper solution has a deep blue color up to the point 
midway between the plates and the upper zinc solution, of 
1.1 specific gravity, is clear like water, and when the divid- 
fX^^^ ing line between them is sharp. If the blue rises higher, 

~^;^^]\~ I reduce the external resistance or short-circuit ; if it sinks 
much below the middle, leave it on open circuit a few 
hours. The cell normally should remain closed on a resist- 
ance and never jarred nor the plates within be disturbed. 
Copper sulphate crystals should always be seen in the bot- 
158 Gravity Crowfoot ^°^- When the zinc solution becomes too heavy, causing 
* salt to form on the upper parts and copper on the zinc, or 
the specific gravity reaches 1.2, remove the top liquid by means of a syringe to an 
inch below the zinc, and replace with water slowly, so as not to disturb the 
solution below. When metallic copper forms on the zinc, take out the plate, 
scrape off the mud, chip off any cake formation, and after dropping in large 
crystals of bluestone (if needed), replace the zinc and cover. 

4 Dismounting. — Take out the plates and save the top clear liquid to start the 
new cells. With a hammer and knife remove the hard crust from the zinc and 
the deposit from the copper. See that the attached wire 
is firmly riveted to the copper plate and that there is no 
break in the insulation. 

5. The Eagle cell isforportahility.—F\\\ the lead jar (fig. 
159), whose inner surface has been brightened, one-third or 
one-fourth full of copper sulphate and cover with two- 
inch thickness of pressed excelsior, sponge or sawdust on 
which rests the zinc. Wooden sticks suspended from the 
rim prevent the zinc from touching the jar. Pour in 
water until it covers the zinc and short-circuit for three 
or four days. Let the jar stand on wood soaked in 
paraffine or on glass. 

id) Copper Oxide Cell (Fig. 160). 

159. Eagle. 

1. Plates of zinc and of copper oxide stand in a one- 
fourth solution by weight of caustic potash. ^ = about 0.8 volt. R of the 
5 by 8 inch cell with oxide between two zinc plates is 
about 0.07 ohm. The cell is for either continuous or inter- 
mittent work. 

2. Mounting. — Place the potash in the jar, and pour in 
water until its level shall be ^ inch above the oxide plates 
when in position. Stir with a stick at intervals so as not 
to cause too great rise of temperature until the salt is dis- 
solved. Pour carefully on top heavy paraffine oil so as to 
form a layer i inch thick. 

Pass the ends of zincs, well amalgamated, through the 
middle hole of porcelain cover and fasten them. Put the 
copper oxide plates in their frames, slip on the hard riib- 
ber separators, pass the ends of the frames through the 
holes in the cover and fasten them. Put plates and cover 
in position. If a strong current is wanted at once, short- 
circuit for ten or fifteen minutes. 

3. Maintenance. — If necessary, move the cell without 
shaking. Glass jars are liable to crack. The top layer of 

oil is very essential and the level of the dividing line previously marked on the 
jar inside should be well above the oxide plates. There is no local action on 
open circuit. All materials are proportioned to be consumed in practically the 
same time. 





160. Copper Oxide. 



PRIMARY BATTERIES. 



117 



(e) Bichromate Cell (Fig. 161). 

1. Zinc and carbon plates stand in a solution of sulphuric acid and bichromate 
of potassium or sodium. E — 2.1 volts. R of 6 by 8 inch cell with zinc between 
two carbon.s = about 0.08 olim. 

The Grenet zincs are submerged only when a current is required. 
The current is very strong for a few hours. 

2. Moiintimj. — To 1 gallon of water in an earthen vessel add from 
1 to 2 pints of sulphuric acid, according to the strength required. 
While the mixture is still hot stir in one pound of bichromate of pot- 
ash pulverized. When cool it is ready for use and is known as elec- 
tropoion fluid. 

3. Maintenance. — Special care is taken to keep zincs well amalga- 
mated; they should, when submerged, reach to the bottom of the 

jar so as to touch a little mercury. The zincs are 
raised out of the solution when not in use ; the carbons 
may remain or not. Draw off some of the old liquid 
when it changes color and add fresh. 

4. The Fuller bichromate (fig. 162) is used with long-dis- 
tance telephones. Pour an ounce of mercury into the porous 
cup, 3 by 7 inches, put in the zinc, fill the cup with water 
and stand the cup with its contents in the jar containing, by 
weight, 6 parts sodium bichromate, 17 sulphuric acid, and 56 
water. Alongside put in the carbon with its cover. 

The zinc remains continuously in the cell, which needs no atten- 
tion for four or five months if not overworked ; otherwise once 
a month. There is very little local action on open circuit. When 
the rich orange color becomes bluish, add crystals. If the color 

is still orange and the cell weak, add acid. If the cell is still not active, renew 

the whole solution. 





162. FuWer. 



XIII— TELEGRAPHY. 



(A) DIAGRAM OF MORSE RELAY TEI.EGRAPH FOR 
LONG LINES (FIG. 1G3). 

The main circuit is drawn full ; the local circuits, broken. The former uses 
the ground ; the local circuits are metallic. The main battery of gravity cells 
in series may be at any point of the main circuit, but a half is usually located 
at each end ; if one of the halves has copper to line, the other must have zinc. 




^- Ll^' f 



Nsw York. 




^- WASniNiTOft. 



163. Diagram of Morse Relay Telegraph for Long Lines. 



All relays of the same circuit should be alike. Many operators read the relay 
and dispense with the local circuit. For 5-mile circuits, 20-ohm sounders may 
take the place of relays and local circuits ; both key and sounder have a com- 
mon wooden base and the thin brass base of the sounder is raised \ inch for 
greater clearness. 

A 150-ohm relay has aboiit 4,320 turns in 30 layers, No. 30 on each core. 

A 4-ohm sounder has about 470 turns in 10 layers. No. 24 on each core. 

A 20-ohm soxmder has about 938 turns in 14 layers, No. 25 on each core. 

It is plain from the above diagram that all relays and sounders will respond 
to any key in the circuit and to one key only at a time if 
its switch is open. If a record is desired, a self-starting 
tape register takes the place of the sounder. 



(B) TELEGRAPH CODE. 

The dot, dash and space are the three Morse signals, 
and different combinations of them form the letters. 

The dot (E) is made by a momentary downward .stroke 
of the key lever. This is the unit of time. The dash (T) 
is made by holding the key down as long as it takes to 
make 3 dots. A space as in A occupies the time of 1 dot ; 
a double space, as in R, equals 2 dots. 

The space between letters is equal to 3 dots; between 
words, 6 dots ; the sentence space is filled in by a period. 

(118) 






164. 



TELEGRAPHY. 



119 



The Morse Code. 



A 


_ __— 


IJ 




C 


_ — _ 


I) 




K 


— 


V 




c 


— . — 


II 


_ — c_ .» 


I 


— — 


.1 




K 
I, 




yi 




X 


____ _ 





^ _ 


r 






1 Wait n moment. 




4 Stiirt luf. 




5 llavo you anything? 




7 Are you reaily ? 




8 Busy on other wire. 




9 Important, eive way. 




13 Do vou understand ? 




18 What's the matter? 




30 Close station. 




44 Answer quickly. 




92 Delivered. 




134 Who is at the key ? 









S I 
K <) 



( ) I>X 



S SX 






Abbreviations. 



Ahr 


Another. 


Ans 


Answer. 


Ck 


Check. 


Col 


Collect. 


D 


Degrees. 


Fm 


From . 


DII 


Deadhead. 


GA 


Go ahead. 


GB 


Good live. 


GM 


Good morning. 


GN 


Good night. 


G K 


Gov't rate. 



Msk 


mistake. 


N .^I 


No mote. 


O 1} 


OHicial liusiiioss. 


K 


All right. 


Opr 


Operator. 


Pd 


Paid. 


QK 


Quick. 


K 


Kepeat, are. 


S 


Station. 


Big 


JSigtiature. 


i; 


You. 


1 


Keady. 



(C) FORMS OF MESSAGE. 

Between operators whose calls are S ami J : 

Smith. — "Come down on twelve o'clock train if you are off duty." 
Jones. — "Shall take six p. m. train." 

The call, message, and acknow'ledgment in which Jones fails at first to receive 
the word "twelve," and missends the word "take," occur thus: 

Smith.— J JJJSJJJSJ 

Jones. — III J 

Smith. — II Come down on twel 

Jones. — G A on. 

Smith. — On twelve o'clock train if u r off duty 

Jones. — O K Shall taken __^ _ _ _ take six p m train J 

Smith.— O K S 

Regular commercial or military message; 

Fort Monroe, Va., July 30, 1901. 
John B. Thomas, 80 State street, Richmond, Va. 
"When w^ill you reach Old Point".' Telegraph collect. W. J. Bodell. 

It would be telegraphed as follows : 
, No 45 F S 7 Paid Fort Monroe Va :^() to John B Thomas 80 State street, Rich- 
mond Va. "When will you reacli Old Point. Telegraph collect Sig \V J Bodell. 

"No 45 F" indicates that this is the forty-fifth message sent from Fort Mon- 
roe whose office call is F. "S" is the sending operator's personal call. "7" 
indicates the number of words in the body of the message to follow. "Paid" 
indicates that the message has been paid for; otherwise the word is "collect " or 
"DH" (deadhead). The year and month are omitted. A period immediately 
Itrecedes the body of a message and "Sig" always follows it. The receiving 
operator whose call is " A " sees that the message is apparently correct, verifies 
the number of words and telegi'aphs, "OKA." 

(D) ADJUSTMENTS OF INSTRUMENTS. 

1. Key. — Loosen the binding nuts and turn the trunnion screws close up so 
that the platinum contact points will touch squarely, then turn each slightly 
back so that the key lever moves freely up and do\\Ti without lateral movement. 
If necessary rub the contact points with fine emery occasionally to prevent 



120 HANDBOOK FOR ELECTRICIANS. 

" sticking." The vertical screws of the key should allow a small movement of 
the key lever with a moderate spring pressure. See that all the binding screws 
are tight and that the switch is firmly pivoted by its screw and scrapes well 
into its position when closed. 

2. Relay {or sounder). — The trunnion screws, as in the key, should allow free 
motion to and fro (or up and down) without lateral movement. Next adjust 
the front (or lower) contact screw that the' armature may not strike the magnet 
cores or approach nearer than the thickness of writing paper ; withdraw it even 
further if the armature "sticks." The back (or upjjer) binding contact screw 
should allow small play, but sufficient to give a distinct sound. Adjust the 
screw of the spiral spring until the relay (or sounder) strikes with the key. 
Finally see that all of the binding screws are tight. 

(E) INSTRUCTIONS FOR OPERATORS. 

1. Keep key closed except when sending. If no current is on make sure that 
the trouble is not in your station ; for this purpose touch a short piece of copper 
wire across the main wires entering the station to observe a spark or taste with 
the tongue. If a spark is seen or a current is tasted, the trouble is probably in 
yoiir station. 

2. Keep instruments screwed to the table and constantly in adjustment so that 
relay, sounder and key strike together ; that all binding posts and screws are 
tight; that the ends of wires entering posts project through them and are bent 
around; that no dust, books, papers, etc., accumulate on or about the instru- 
ments The table should be screwed down, and large enough to rest the elbow 
in sending. Never put instruments on a window sill or expose them to the 
weather. 

3. To prevent instrument from working when not required, shunt it out. 
Never screw down the armature lever nor alter the spring nor detach the wires. 

4. To call a station, first adjust to make sure the line is not in use ; if not, open 
the key, make the call three or four times and sign your own call. Repeat until 
answered, when close the key. 

5. To answer a call, wait imtil you hear the signature, then open the key and 
as soon as the distant key is closed repeat the letter "I " two or three times, or 
"O K " once, signing your own call. Close the key. 

6. To send a message, call the station as above. When it is answered, open 
the key, send the message and close the key. If a mistake occurs make inter- 
rogation or six dots and begin with the last word sent correctly. Invariably 
observe the "forms" of message above. If no "O K" is received, the call, 
answer, and message are repeated. 

7. To receive a message, answer the call and prepare to write down the mes- 
sage. The instant a word is missed, break and telegraph "Or A" (go ahead) and 
the last word received. But if all that precedes is desired, telegraph " R R. " 
In a regular message verify the number of words in the body before sending 
"O K." If the check does not verify, the sender must give the initial letter of 
each word until the mistake is found. 

8. In the body of a message abbreviations do not occur, numbers are spelled 
out, periods occur between sentences but not at the end, and compound words 
and names of places covmt for one word. 

9. Care should be taken to send uniformly. It is more difficult to send well 
than to receive well. Few operators send and receive 40 words per minute ; 30 
words is very rapid ; the average speed does not exceed 20. Five letters count 
lor the length of one word. 

(F) DIRECTIONS FOR BEGINNERS. 

1. (1) Memorize the alphabet. (2) Learn with the aid of an instructor to 
write Morse with the key. (3) Send and receive alternately with a companion 
at the same instrument. (4) Send and receive with a companion at a distant 
station. (5) Complete the practice in a regular telegraph office. A good oper- 
ator should often be consulted to avoid acquiring a faulty sending. 

2. To write, grasp the button with thiimb under the edge and first two fingers 
above it; allow the wrist to be perfectly limber; rest the arm on the table at or 
near the elbow ; let the grasp be firm but not rigid ; never allow the fingers or 
thumb to leave the key nor the elbow to leave the table ; avoid too much force. 
The motion to be imparted is directly up and down, principally at the wrist. 
Guard against rigidity of the muscles, graduate your writing to the capacity of 
the receiver and never crowd him. 



TELEGRAPHY 



121 



3. To receive, always write with pen or pencil the words as they come from 
the sounder ; do not attempt to anticipate. A tendency to anticipate causes 
errors and delays progress. It is good practice to have messages sent backwards 
from a hook. Break in as soon as a word is missed and do not wait nntil several 
words are lost in the hope of catching a sufficient number to guess at the mean- 
ing of the message. Always break in at the first word missed and telegraph 
"G A" and the last word received; this will regulate the .sending. In a short 
time words like "and," "the," etc., will always be recognized and later whole 
phrases without effort. 

4. In the first practice take the following exercises in turn: (1) Make dots in 
succession until a uniform rate of about 120 per minute is accpiired. (2) Make 
dashes in succes.sion until a uniform rate of about 60 per minute is obtained. 
(3) Practice E, I, S, H, P. (i, until each can be made at will correctly. (4) Make 
the spaces uniform in O, C, R, Y, Z, etc. (5) Be careful to proi)ortion short and 
long dashes accurately in T, L, M, 5. 0. (6) Avoid lea\ing too long space between 
the dash and the dot next to it in A, U. V, 4 and inN, D, B, 8. (7) Practice the 
mixed combinations in F, G. J, K, Q, W, X. 1, 2, 3, 7, 9, period. 

5. Follow "instruction to operators" given above. 

(G) U. S. ARMY AND :N^A\T SIGNAL CODE. 

(1) WIGWAG ALPHABET. 



A. 

B. 

C. 

D. 

E 

F. 

G. 

H 

I-. 



2112 
.121 
.222 
..12 
2221 
.2211- 
-.122 
....1 



a after. 

b before. 

c can. 

h have. 



J. 
K. 
L- 
M. 
N. 
O. 
P. 

Q- 

R. 



1122 

.2121 

.221 

.1221 

...11 

-.21 

1212 

1211 

.211 



S...- 
T... 
U... 
V-- 
W... 
X... 

Z... 

1. .- 



. 212 

...2 
-112 
1222 
1121 
2122 

..111 
2222 

.1111 



.2222 
.1112 
.2221 
.1122 
.2211 
.1222 
.2111 
.1221 
.2112 



(2) ABBREVIATIONS. 



n not. 

r are. 

t---- the. 

u vou. 



ur your. 

w word. 

wi with. 

y why. 



X X 3 " numerals 

follow" or ' 'numer- 
als end." 

sig. 3 signature. 



End of a word 3 

End of a sentence 33 

End of a message 333 

Ave, " I understand " 22. 22. 3 

Cease signaling 22. 22. 22. 333 



Repeat last word 121. 121. 3 

Repeat last message . . 121. 121. 121. 3 

Error 12. 12. 3 

Move to the right 211. 211. 3 

Move to the left 221. 221. 3 



(3) CODE CALLS. 



Cipher "A" Use. 
Cipher "B" Use, etc. 
Navy List Use. 
Vessel's Numbers Use. 



A. S. U. Action Signals Use. C. A. U. 

I. C. U. International Code Use. C. B. U. 

T. D. U. Teleg. Dictionary Use. N. L. U. 

G. L. U. Geograpliical Li.st Use. V. N. U. 
G. S. U. General Signals Use. 

(4) INSTRUCTIONS FOR SIGNALING WITH FLAG, TORCH, HAND LANTERN, OR 
BEAM OF SEARCH LIGHT. 

Tliere are but one position and three motions. 

The first i)<>sition is with the flag held vertically in front of the center of the 
body, butt of staff at height of waist, signalman facing squarely toward the 
station with which it is desired to communicate. 

Tlie first motion, or " 1," is a motion of the flag to the right of the sender, and 
will embra<'e an arc of 90 , starting with the vertical and returning to it, and 
will be made in a plane exactly at right angles to the line connecting the two 
signal stations. 

The second motion, or "2," is a similar motion to the left of the sender. 

To make the third motion, "front." or "3," the flag is waved to the ground 
directly in front of the sender, and instantly returned to the first position. 

Numbers wliich (X"cur in the body of a message must be spelled out in full. 
Numerals may be used in signaling between stations having Naval Signal Books, 
using the Code Calls. 



132 HANDBOOK FOR ELECTRICIANS. 

(5) TO SEND A MESSAGE. 

"To call" a station, signal its initial or "call letter" imtil "acknowledged." 
"To acknowledge," signal "Aye," followed by its initial or "call letter." 
Make a slight pause after each " letter," also after each "front." 

(6) FOG SIGNALS. 

To apply this code to the "fog whistle " or "fog horn :" 
One (l)'toot (abont one-half second) will be "one" or "1." 
Two (i) toots (in quick siiccession) will be "two" or "2." 
A blast (about two seconds long) will be "three" or "3." 

The signal of execiition for all tactical or drill signals will be one (1) long 
blast, followed by two (2) toots in quick succession. 
The ear and not the watch is to be relied upon for the intervals. 

(7) TO SIGNAL WITH FLASH LANTERN, HELIOGRAPH OR SEARCH-LIGHT SHUTTER. 

Same as in fog signals; substitute "short flash " for "toot." and "long steady 
flash" for "blast." The elements of a letter should be slightly longer. 

"To call" a statioi. — Make the initial or "call letter" until "answered." 
Then turn on a steady flash until answered by a steady flash. The station 
called will •■acknowledge" and cut off its flash and the calling station will pro- 
ceed with the message. 

No abbreviations will be iised in the body of the message. 

All other conventional signals are the. same as for flag or torch. 

(H) ARTIIiliJERY FIEIXG CODE. 

T A = Target angle. 

S A = Shot Angle. 

TAD 23 M 45 = Target angle is 23 degrees and 45 minutes. 

F F = Fire. 

C S = Close station. 

T T A = Take tartlet anajle. 

T A 3 = Target angle No. 3. 

2 R F = No. 2 gun is ready to fire. 

R T A 2 = Repeat target angle No. 2. 

R S A 4 = Repeat angle No.^4 shot. 

R U R = Are you ready V 

R U R F = Are you ready to fire '? 

(I) setti:n^g up the hei^tograph. 

1. Always spread the tripod legs wide enough for a good base and press them 
firmly into the groiind so that the top is level. 

2. The sun mirror has a peephole at the center ; the station mirror, a paper 
disc. Both in position on the bar can be turned horizontally or vertically by 
tangent screws. 

3." When the sun is in front of the operator while facing the distant station, 
the sun mirror only is required : vrilh the sim in rear, both mirrors should 
be used, althoiigh a single mirror may often be worked to advantage with the 
sun well back of the ojierator. In the former case, the rays of the sun are 
reflected from the sun mirror direct to the distant station : in the latter, they 
are reflected from the sun mirror to the station mirror, thence to the distant 
observer. 

4. lT'(Y/i one mirror. — Attach the mirror bar to the tripod: insert and clamp 
in their appropriate sockets the sun mirror and the sighting rod, the latter with 
its disc turned do^vn. Sight through the center of the mirror and turn the 
mirror bar, and raise or lower the sighting rod until the center of the mirror, 
point of sighting rod. and distant station are accurately in line; then clamp the 
mirror bar firmly to the tripod, taking care not to disarrange the alignment. 
Turn up the disc of sighting rod. 

Move the mirror by means of slow-motion screws imtil the "shadow spot" 
from the unsilvered peephole falls upon the disc of the sighting rod. The 
flash -SN-ill then ])e visible to the distant observer. 

The shadow spot must be kept in the center of the disc while signaling. 

Attach the screen to its tripod and place it, close to, and in front of the sight- 
ing disc, so as to intercept the flash. 



TELEGRAPHY. 123 

5. With firn viirrnm. — Clamp the mirror liar fliap:onally across the line of 
vision to the distant station ; flamp the sun mirror, facinij the sun, to the end 
of mirror bar witli tanf:Cent screw attachment; and the station mirror, facing? 
the distant station, to the other .socket. Stoopintc down, the liead in rear of 
and near the station mirror, turn the sun mirror by means of its .slow-motion 
screws until the whole of the station mirror is seen reflected in tlie sun mirror, 
and the unsilvered spot and reflection of the paper disc accurately cover each 
other. 

Still looking into the sun mirror, tnrn the station mirror until the reflection 
of the distant station is l)rought accurately into line with, or is covered by, the 
unsilvered .spot and the reflection of the disc ; after this, the station mirror 
must not be touched. 

Now stepping behind the sun mirror, throw upon the station mirror a full 
flash from the sun mirror so that the "shadow sjjot" falls upon the center of 
the jKipcr disc. The flash will then be visilile at the distant station. 

The shadow spot must be ke])t in the center of the paper disc while signaling. 
The intercepting screen should allow room for adjusting the sun mirror. 

(J) LOCATING FAULTS. 

Most line faults are of three kinds— a break, an escape, or a cross. 

1. The break may be: (1) comi)lete, as when the line is severed or a key left 
open, etc. — all instruments in the circuit cease to work; or it may be (2) partial, 
as from a rusted joint or a loose contact, etc., which increases the conductor 
resistance — all ijistruments work equally feebly or 
not at all. A complete break, as in fig. Kio, is found f 
by inserting at either end a battery, one .side of which 
is to earth, as .shown. The lineman then proceeds 
along the line from the other .side of the battery con- |,_ 

necting, temporarily, at different points, tlie line to 

earth through the "tongue or galvanometer. Near the battery he gets the ful' 
current. If at any point he fails to get it. he has passed the comjjlete break. 
It is important to note the current strength from the taste or deflection near the 
l)attery; if, then, at any place it suddenly diminishes, but is still noticeable, a 
partial break has probably been passed. 

2. An escape (fig. 16.")^) arises from defective insulation at some point, as when 
a hare wire falls to ground or touches a tree or building, or the covering of an 

insulated wire is injured, etc., and allows a por- 
tion of the current on the line to escape. Instru- 
uneciually. Those near the battery 
stronger, those beyond the escape are weaker 
165a. than usual. 

The lineman may inspect the line to see if any 
pole, tree, building, etc. , has come in contact with the wire. If it can not be found 
in this way he may open the line at some point. If an examination at the liat- 
tery end still shows the escape the fault is on the side of him towar<ls the battery; 
but if it has disap])eared the fault is on the otlier side of him. He proceeds 
accordingly to o])en the line at another ])oint. having closed the first. 

'.\. Across (fig. 1()(5) is a fault caused l)y two parallel lines coming in contact; 
the instruments on one line respond to those in the other. Inspection of th ^ 
line may reveal the fault. Or open both of the dis- 
tant ends. Starting from the battery the lineman CT^ 
opens the line at some point : if he gets a current he 



W^»^ 



"i^*'~m— 



r I I [\ /T [ \ tion of the ci 

r<li <iit1^iiM till i-l -Aft/^ li'M -' 4^\4!L« 

,^.n.p.,. |.,. r| - imr ,■ j.-~.j. ^^j- .^^^ StrOUgCr, 






has not reached the fault. tawr 

(renerally on a long line having several stations 
the fault is first located as ])etweeji two stations, •^*'- 

from one of which a lineman is sent out. 

Periodic tests of the conductor and insulation resistances of every important 
line should be made regularly and the results kept in a record book. 

(K) THE TELAITTOGRAPII. 

(a) DESCRIPTION. i'KIXCIPLES .\ND OPERATION. 

1. Trnnxmitter — By means of two light rods attached to the transmitting 
pencil neiiv its point the arliitrary motions of writing or drawing are resolved 
into simple rotative or oscillatory motions of two pivoted arms, located on either 
side of the writing platen. These arms are included in the line circuits and 



124 HANDBOOK FOR ELECTRICIANS. 

carry at their extremities small contact rollers which move to and fro upon two 
rheostats, or resistance coils, these being so connected through the arms to the 
line and to the source of energy as to act both as adjustable shunts and as 
rheostats in the line circuits. By this method the voltage supplied to the line 
is made to vary with the position of the pencil upon its writing platen and 
definitely variable writing currents are transmitted. 

2. The receiver principle is equally sim'ple. The variable line currents com- 
ing in over the line wires are led through two vertically movable coils, each 
suspended in a strong uniform magnetic field by a well-sweep arrangement, 
from which they derive the name of "buckets." 

Each coil is supjilied with an adjustable retractile spring which tends to 
oppose the movement of the coil downward through the field. It is evident 
that for given values of the line currents each coil will have a definite position 
in its respective magnetic field, depending upon the tension of its retractile 
springs. The vertical motions of these receiver "buckets," due to the varying 
line currents, are used to cause rotative motions in two pivoted arms, similar to 
those at the transmitter, which motions, through another system of light rods, 
compel the receiving pen to exactly reproduce the motions of the transmitting 
pencil. 

3. To accomplish the pen-lifting at the receiver an automatic device is used, 
consisting of an induction coil at the transmitter, having two secondary wind- 
ings and performing the double function of pen-lifting and reducing friction. 
The primary circuit of this coil is entirely local at the transmitter, and includes 
an interrupter and a shunt circuit controlled by the platen. 

4. The vibratory secondary currents are superimposed upon the writing cur- 
rents, and serve to keep the receiving pen in continual though imperceptible 
vibration, reducing friction in the moving parts to a minimum. The normal 
writing pressure of the pencil tipon the transmitter platen opens the shunt 
circuit and causes an increase in the strength of the secondary vibrations. 
This operates a vibratory relay inserted in one of the line circuits at the receiver, 
opens a local circuit, and causes the armature of the pen-lifting magnet to be 
released and the pen is allowed to rest upon the paper. 

5. Lifting the transmitting pencil from the platen decreases the strength of 
the vibrations, closes the local receiver circuit, the pen-lifting magnet attracts 
its armature and raises the pen clear of the paper. 

6. The shifting of the paper at the transmitter is done mechanically by means 
of the master switch. The same motion of the switch operates an electro-mag- 
netic device over one of the line wires, which automatically and positively shifts 
the paper at the receiver a corresponding amount. 

The paper, 5 inches wide, is supplied in conveniently detachable rolls, which 
are mounted in brackets attached to the backboard of the instrument. For 
signaling, a push button at the transmitter operates a call bell at the receiver. 

7. The transmitting pencil is a simple adjustable lead pencil. The receiving 
pen is made on the principle of the ordinary right-line drawing pen, so modified 
as to make perfect lines regardless of the direction of motion, and capable of 
holding an ample supply of ink. 

8. The inking device consists of a bottle or supply well, with a hole and stopper 
for refilling, and also with a second small hole in the side of the well. This hole 
is below the surface of the ink, and the top of the well being corked and air- 
tight, the ink is prevented from flowing out by the pressure of the external 
atmosphere. 

The small hole is located at the unison point, and whenever the paper is shifted 
the pen returns to this position and automatically dips its point into the ink 
which stands at the mouth of the hole. Capillary attraction is sufficient to 
completely fill the pen, and, resting in the hole as it does, the point does not 
clog up with dry ink when not in use, but is always ready to start writing with 
a full fresh supply. 

(b) EXPLANATION OF DIAGRAM. 

1. Transmitter. — The motions of the transmitting pencil A are conveyed 
through the pencil arms B B', and pencil arm levers CC to contact arms DD', 
which carry contact rollers E E' , these contact rollers bearing upon the periphery 
of rheostats F F' , the terminals of these rheostats being connected through 
master switch G to the positive and negative poles of a suitable source of elec- 
trical energy, indicated by battery H. The contact arm D' is connected to the 
right line through one of the secondaries of the induction coil 1, and through 
the right-line contacts G^' of master switch, when the master switch is in the 




107. Telautoi^raph with Cover Removed to Sho^y the Workinjj Parts. I:i4 



TELEGRAPHY. 



125 




a^:.Q. 



Tl^H>^$^lT"TCf\ 



169. Transmitter and Receiver. 



126 HANDBOOK FOR ELECTRICIANS. 

writing position as shown. The contact arm D is connected to the left line 
through the other secondary of the induction coil / through the left line con- 
tacts G2 of master switch. The writing platen J is pivoted at K K' , and when 
pencil is off, the platen closes upper contacts L L' , shunting resistance / around 
the primary winding of induction coil I. The vibrator M is in circuit with the 
primary of induction coil / and battery H, and rapidly vibrates, the current 
passing through the primary of the induction coil, thus causing a vibratory 
current to traverse the right and left line wires, the strength of this vibratory 
current depending upon the position of the platen J\ when this platen is 
depressed by the pencil in the act of writing the shunt around the primary of 
induction coil /is open, consequently the strength of the vibratory currents on 
line is increased ; this increased strength of vibration actuates the pen-lifting 
relay /», (in receiver). The paper at the transmitter is shifted by moving the 
handle N of lever O, which is connected to shaft P, which carries the pawl Q, 
engaging the ratchet wheel -R, mounted on shaft of paper-shifter roller ;S'. 
Each movement of this handle iV^to and fro causes the roller S to rotate, which 
moves the paper forward. The shaft P also carries master-switch contact 
plates G, Gl, G2, which open and close the line and battery circuits, according 
to the position of handle N; circuits being closed and instrument in sending 
position when handle N rests in position shown by arrow. The movement of 
the handle N in the opposite direction cuts the instriiment out of circuit. The 
handle is locked in either position by lever P, and can not be released except by 
pressing point of pencil A on button T . A signal-switch push button is shown 
at U\ this switch when operated throws current of positive polarity through 
right line, which rings receiver bell u, as hereafter described. 

2. Receiver. — The motions of receiver pen a are caused to diiplicate the motions 
of transmitting pencil ^4 through the pen arms h b\ pen-arm levers c c', which 
are mounted on shafts carrying sectors d d . Light metal bands e e' are attached 
to the peripheries of sectors d d' and carry at their lower ends coils (or "buck- 
ets ") //', and their upper ends are attached to springs g g'. The coils / /' are 
movable in the annular spaces between the poles of the magnets /; and i, and h' 
and ?■'. Coil /is in circuit with Morse relay ^ and the left line, and coil/ is in 
circuit with pen-lifting relay m and the right line. As the transmitting pencil is 
moved its motions are transmitted to contact rollers E E', the strength of cur- 
rent on line is varied, the currents becoming stronger as the rollers approach 
the positive eiads of the rheostats F F , these currents traversing line and pass- 
ing through coils//, causing them to take different positions in the magnetic 
fields, opposing the pulls of the springs g g' , these springs being so adjusted that 
tile position of the receiving pen in the writing field will always be tlae same as 
the position of the transmitting pencil on its writing platen. 

3. The depression of platen J, causing a strong vibratory current to traverse 
line, causes the armature of pen-lifting relay m to vibrate and interrupt the 
circuit of pen-lifter m' , thus releasing the armature of pen-lifter and lowering 
the pen-arm rest so as to allow the pen to come into contact with the paper. 
Upon raising the transmitting pencil from its platen the vibratory current will 
be weakened, the armature of pen-lifting relay m ceases to vibrate, closes the 
circuit of pen-lifter m' , which attracts its armature and thus lifts the pen from 
the paper. 

4. The paper-shifter o' is an electro-magnetic device and is controlled by the 
Morse relay / the armature of this relay closing the circuit of the shifter through 
its forward contact when the relay j is energized by line current through the 
master switch by the movement of handle N in the position shown by arrow. 

5. The signal bell u, which is of low re.sistance, is thrown in parallel with the 
right-line coil, or "bucket"/', when no current is passing through the paper- 
shifter, conseqiiently when signaling current passes over right line the bulk of 
the current i)asses through the bell, rather than through coil/'. 

6. The ink well (an ordinary glass bottle) is shown at p, the receiver pen a 
entering the opening p ' and receiving a fresh supply of ink every time the paper 
is shifted, the pen resting in this opening and in contact with the ink when the 
instrument is not in use. 

(c) Installing. 

The instruments are furnished with a suitable backboard, the connections 
being made between the instruments and the circuits on the backboard by auto- 
matic contact pins, so that the instruments can be put on and taken off readily. 
The terminals on the backboard for connecting to line and battery are plainly 
marked so that the proper connections may be easily made. 




lf>K. In Operation. 



TELEGRAPHY. 127 

{(I) Operation. 

1. To u'rite. — Depress button with pencil point and pull lever towards yoii a 
full stroke; relea.se button ^\"ith lever in this position, and write with firm pres- 
sure on paper. 

2. To. shift paper. — Depress button, holding it down until you have moved 
lever back and forth its full stroke as many times as you wish to shift paper, 
then release button with lever in position towards you. 

3. To lunuj up. — Depress button, allowing lever to rest in position away from 
you. Always, after writinij^, leave the lever in position from you. 

(e) Care of Instruments. 

The care of the instruments consists mainly in keeping the ink bottles properly 
filled with the ink which is .supplied for that jjurpose, the occasional cleaning of 
the pen jxunts, and the insertion of fresh rolls of paper which is supplied for 
that purpose. 



XIV.— TELEPHONY. 



(A) APPARATUS AND CONNECTIONS. 

Fig. 170 gives details of the apparatus and connections of the bridge form of 
the American Bell telephone: 

1. Western electric call box, 500 ohms in armature, 1,000 ohms in bell magnets. 

2. Long-distance induction coil, 1,000 ohms in the secondary. 

3. Solid back transmitter, 3 ohms. 

4. Two double-pole watch receivers with head strap, 75 ohms each. 

5. A porous cup, or a carbon cup Leclanche, the latter preferred. 

6. Warnock hook. 

Full lines represent electric circuits ; those drawn heavy show the local or 
transmitter circuit. 

7. When one tiirns the crank shaft in the call box to ring, a cam thereon causes 
the whole shaft to slide in opposition to a spiral spring, i inch to the left, into 
contact at ^4. The generator's armature coil is thereby thrown into circuit; its 
terminals are the insulated pin B bearing against a spring and the armature 
shaft leading the current to metal frame and A. 

8. When the receiver is off the hook, lever scrapes into good contact with both 
springs at F; when on, it opens these points. Both posts of the watch receiver 
T T are mounted on a triangular plate of ebonite inside the case. 

9. Polarized bell. — The U-shaped, permanent magnet iV 6' screwed at i\^to the 
backpiece of the electro-magnet, renders both poles of the electro-magnet north, 
and by induction, the middle of the armature where it is pivoted, north. Both 
armature ends are, therefore, south; i. e., either armature S-end stands opposite an 
JV"-pole. When a positive current enters the magnet coils, one iV-pole is neutral- 
ized and the other is made stronger so that the latter attracts its armature end. 
A negative C makes the other iV-pole attract its armature end, and so on. As 
there is no spring to be overcome, a polarized relay is very sensitive and deserves 
attention on account of its importance in the service. For the magneto which 
generates the alternating -i- and — currents, see page 46. 

(B) MAGNETO, BELI., AND SECONDARY COII.S. 

The magneto, bell, and secondary coils of each station are joined to mains — 
In parallel or bridge (fig. 171.) In series (fig. 172). 





17 J. Parallel Telephone bvaiion. 



172. Series Telephone Station. 

The three main coils have few turns of wire and 
low resistance, and operate in series. 



Majjncto circuit, normally short-circuited, has 
the sliunt opened autdniaticiilly at A by the crank 
shaft slidini; to the riijlit }^ inch when rotated, so 
that the ringing current goes to line. 



1. All bells are permanently bridged. They will 
respond to the maKneto's slow alternations but 
their iiniie<lance acts like an infinite resistance to 
the rapiiUy altrrnating sp<'akiiiK current. 

2. JhiK'ni-to ciriMiit, normally open at^, isclosed 
automatically by the. crank shaft when rotated, so 
that the generated current goes to line. 

3. AVTien the receiver is on the hook lever for calling, the circuit between terminals is — 

1. Bells, 3. 1. H,L, .4, bells, 3. 

4. When receiver is on and the crank is turned to call, the circuit is — 

1. A, armature, 3.\ 1. H, L, A, armature, bells, 3. 

1. Bells, 3. / 

5. When the receiver is taken off for talking, the circuit is — 

1. Bells, SA r , ■ ■. ■ I. E,S, F, 3. Local circuit is— B, T, P, H, L. 

' [ Local circuit is — 
B, T, P, F, L. 



S, F, 3. '> 
R, F, 3. j 



(128) 



TKLKI'HOXV. 



129 




P=-^% 






170. Complete Details of Bridge Telepiione. 

(Porous cup and Ilaydt-ii cells shown ; uso one kind only.) 



130 HANDBOOK FOR ELECTRICIANS, 

6. Five bridge or four series telephones are the limit on one circiiit. When 
more are required (as will rarely happen) a central exchange or a party line will 
be necessary. The main circuit is always metallic. On short, busy lines, as 
between range finder and four mortar pits, it will be advantageous to run four 
main wires — two for talking and two for signaling. All telephones on the same 
circuit must be alike. 

(C) TO USE. 

Give the bell crank one sharp turn, take the receiver from the hook, place it 
firmly against the ear and when the unhooking at the distant station is heard, 
give the number wanted if it is "Central " or the name desired if it is a party 
line. 

Speak directly into the transmitter, with the lips close to it, in a low, distinct, 
and deliberate manner ; never shout. Be guided by the listener as to your dis- 
tance from transmitter and your articulation. When finished, hang the receiver 
on the hook and give a half turn to the crank. During storms and when closing 
for the day, shunt out the instrument by the lightning-arrester plug. Keep the 
instrument free from dust, the cells clean, and the solution at normal strength 
and height. 

(D) TELEPHONE FAUETS AKD THEIR LOCATION. 

The three classes liable to occur are: (1) An open circuit at a joint, post, 
spring contact, or where rust is seen; (2) a short circuit in a magnet coil, cord, 
or where dust and filings collect; (3) derangement of magnets, bells, switch, 
transmitter, receiver, or battery. 

An intermittent fault is more difficult than a lasting one to find, as, for exam- 
ple, when a line grounds only when swayed by the wind, or the resistance of a 
joint keeps changing, or the two wires of a cord touch only when it is in a cer- 
tain position. To locate a fault promptly, a knowledge of the circuit and experi- 
ence are essential. 

The first steps in locating a fault are to question the user, to look carefully 
over the accessible parts, to try to ring, to listen for the characteristic noise in 
the receiver from scratching on the transmitter, and to determine at once 
whether the trouble is in the station or outside of it by cutting oiit the station from 
the rest of the circuit if necessary. The symptoms differ somewhat in bridge 
and series systems. Three cases arise : 

1. Station can not ring. — See if the bell's armature is free, if wire joints around 
bell, hinges, hook, etc., are good, and if both shaft contacts at the magneto 
operate. If a bridge telephone, there may be a short circuit between its mains, 
in which case the crank tiarns with difficulty ; or there may be a break in its 
magneto or its bell circuit, but not if the bell rings after detaching the line wires. 

In a series telephone, there is probably an open circuit ; it is outside if the bell 
rings after connecting the line posts by a short wire or by the lightning-arrester 
plug. If in this case there is no ring, the trouble is in the ringing circuit. 

2. Station can ring but cannot hear. — The speaking circuit is open or shunted 
at some point. If scratching or blowing into the transmitter is heard, the sta- 
tion's receiver circuit must be in order and the fault probably lies in the trans- 
mitter circuit of the distant station. 

3. Station can ring but can not be heard. — The fault is iwobably in the local 
transmitter circuit. But if scratching on the transmitter is heard, the fault lies 
in the receiver circuit (receiver, secondary and lever contacts) of the distant 
station. 



TELEPHONY. 131 

(E) IN GEN^ERAL. 

The xiSTtal induction noises heard in a receiver show that the main line and 
your station receiver circuit are in order ; although the secondary may in this 
case be short-circuited. If so, hlowini,' into the transmitter can not he heard. 
To verify, oi)en the line and if the noises do not cea.se their caii.sc lies within. 

Cross talk, humming of motors, Morse clicks, etc., show that tlie telephone 
line runs i)arallel with a foreign wire for a greater distance on one side of it than 
on the other, or that there is leakage through the ground terminals. To i)revent 
these noises, telephone lines are usually metallic, and if parallel A\ith other wires 
they should run for eipial distances on opposite sides of them. A twisted metallic 
or a balanced line has no induction noises. 

Creaking or boiling sounds in the receiver are often due to bad contacts in the 
local or transmitter circuit. 

The set entire is not in good adjustment unless the bell hammer responds 
l)romi)tly to slow turning, giving two strokes to each turn of the armature, and 
unless light scratching on the backboard is heard in the receiver. The receiver 
should be audible to a good ear at 10 feet distance from low, distinct talking at 
the distant station. 

(F) DERAXGEMEXT GF APPARATUS. 

1. //( magneto. — (a) Short circuit from brass filings, dirt or burnt coils; (h) 
djniamo shaft in the bridge telephone not closing on the sjjring contact and in 
the series not opening when turned; {<■) armature shaft not in contact with 
spring; {(I) weak field magnets ; (e) armature striking pole piece; (/) dust on 
lightning-arrester. 

2. In polarized bell. — (a) Armature striking pole piece, or too distant, or not 
free to move, or not responding promptly ; (b) bells not spaced to receive strokes 
alike, in which case loosen and turn them; (c) magnet too weak to hold by its 
own weight. 

',i. In hook lever. — Not scraping into good contacts; weak spring. 

4. /;/ .^olkl baek trans)nitter. — (a) Breaking of uiica disc, which allows carbon 
granules to fall out ; (b) " packing " of granules, which renders speech inaudible, 
and may often be remedied by moving transmitter quickly up and down ; (c) 
diaphragm rusted, or its rubber hardened, or its spring too tight or too loose. 

5. In receiver. — {a) Diaphragmtooclo.se, or too distant from pole piece. Its 
distance is correct when after removing ear piece and holding the receiver side- 
ways in one hand and tapping with the other, the diaphragm falls partially off; 
if it does not start it is buckled or too close ; if it falls entirely off it is too far 
away: {b) if diaphragm is buckled, replace it; (r) dirt between it and the poles; 
(f/) a break in the circuit, discoverable by touching the ends of the receiver's 
cord to tlie poles of a cell; (c) a short circuit in the cord itself through which 
a series bell will ring and a bridge bell will not. 

6. Inbatterif. — See Fuller bichromate and Leclanche cells. One or two like 
cells in series usually afford sufficient battery power. 

7. 1)1 local in(j f(n(lt.-<. an assistant, a detectcn- galvanometer with dry cell, and 
such tools as knife, small pliers, screw driver, file, and emery are iiseful. 

8. Guard against dust, damj), unsoldered connections, loose wires under 
screw washers or binding posts from shrinkage of wood, breaks or contacts in 
the receiver cord. 

(G) INTERCOMMUNICATING TEIiEPIIONY 

1 Is suitable for twenty or less stations near each other, as in a large biiild- 
ing or in any fort. A cable having one, and in sojne cases two more wires.than 
the number of stations, passes each station. There is no central (fig. 173). 
Any one station can be put into communication with an\' other on that system 
by the operator himself. The left hand figure at each switch designates the 
number of station or instrument to which the switch is connected, and the lever 
must always remain on left hand point except when another station is called. 
No. 1 wishes to communicate with No. :i He moves the lever of his switch to 
the point marked 3. and after ringing him up can carry on conversation. 
When No. 1 has finished talking he replaces the lever of his switch to contact 



132 



HANDBOOK FOR ELECTRICIANS. 



point No. 1. A similar action takes place when any of the other stations wish 
to communicate. This system is specially adapted for commnnication in hotels, 
factories, office buildings, or any place where wires are all under one roof. 
When the distance between the terminal stations is over 500 feet the expense 
becomes high, owing to the niimber of wires required. 




II rlH'h 

I A/vs/jJ 




COMMON RETURN 





173. No Central. 



2. A common battery is a feature of modern systems. In fig. 174 each of the 
ten lines is connected with 10-springs jacks on each of the ten telephones (three 
shown). P is plugged to the No. of the station called, c and c are impedance 



BiTTCnv wrnE 




174. Common Battery, 10 Stations. 



coils on either side of the transmitter circuit to prevent cross talk when more 
than two stations communicate. 

3. The Holtzer-Cabot system is extensively used (fig. 175). 



^' i.i'' 




TELEPHOXY. 



13:3 



(H) A CEXTllAT^ STATIOX SYSTEM 



Sometimes required, is shown for — 
40 line drops, 1 per station, ^4. 
10 clearing-out drops, B. 
10 pings with double cords, C. 
10 listening keys, E, for 10 connections. 
10 sets ringing kevs, F, for 10 connections. 



Operator's transmitter. 
Operator's receiver. 
Operator's magneto. 
Night-bell switch. 
0])erator's telephone battery. 




176. Central. 

2. On this board (fig. 176) ten stations can be put in communication with ten 
others in pairs at one time, by way of the ten twin wire cords (fig. 178), kept 
from getting tangled by running weights. Plug C (fig. 17G), or P (fig. 178), has 
two insulated metal i)arts, knob and cylmder, which are the terminals of the 
t\N'in wires in the cord. 

The line-drop magnet (figs. 177-8) on the board lets plate S fall and thus signals 
th<' number of the station which calls and desires a connection ; its wires connect 
with mains to station: wire » is for a night local call l)ell circuit. 

:{. Tlie •'clearing-out drop" magnet, C (>, in fig. 178, is like the line drop except 
in its winding of finer wire (oOO ohms), soft-iron cover to prevent induction and 
more clo.sely adju.sted armature; it is 
l)ridged across the two wires in the cord 
which connects the two .stations i)laced in 
c-iimmunicatii)n and will, therefore, .signal 
wlieii either station rings "off." 

4. To illustrate the working of a board, it 
is oidv necessarv to take three line dro])s, 
/. /'./■■. in fig. 'l78, two plugs, P and /' , 
and twin wire cord 1 and 2,* one listening 
key. AT, akso one ringing key. A', whose but- 
ton l)eing pres.sed, throws the magneto, al- 
ways running on a large board, into the 
cin-uit of any pair of itlugs. 

5 When plug y is pushed into any spring- 
jack, as at II — 

Its small end knob rai.ses tip .sjjring c from the drop's wire 
the cord wires with one of the mains. 




(ira\ity Orop. 

and joins one of 



134 



HANDBOOK FOR ELECTRICIANS. 



The insulated cylinder next the knob connects at the same time the other 
conductor with the second main line to the station. 

6. Suppose a call comes from station 1 — 

The drop falls, displaying number "1 " to the operator. 

She then inserts either plug, as P, of any pair, say the fourth, in the jack, 
closes the listening key, K, and learns that connection is desired with "40;" for 
example, the circuit being main line, jack '' 1," plug Pand cord, kej^ K, secondary 
and receiver. 

She next inserts the other plug P' of pair 4, presses key K' and rings her mag- 
neto, the circuit being magneto K' , plug P', jack to "40 " and main line. 




178. Three Jacks, Three Drops, One Clearing=out Drop. 

On pressing K she hears station 40's response and then 40 and 1 talking. 
Releasing K, she may give attention to other calls and connections. 

The clearing-out drop C O. of high resistance and impedance, being perma- 
nently bridged across the talking circuit, signals when 40 and I have fini,shed. 
Their circuit was main line, jack, and plug 40, cord twin wire plug, jack and 
main line 1. 



XV.— LAWS, WIRE TABLES, EXAMPLES. 



(A) ELiECTRICAIi QUAXTITIES, THEIR UXITS, AND THE 
I^AAVS OF THEIR REJLATIOXS. 

Each quantity has one unit and every amount is expressed in terms of that 
unit by a decimal nximber. 



I.M-.VNTITV, SVM- 


Df.kinitmn. 


Name of 


A'AI.fE OK PltArTICAI, 


KXA.MPI.F.S, KqII VA- 


iioi,, Law. 




Unit. 


I' NIT. 


LE NTS. 


Difference of 


With electricity pre- 


1 volt, PD. 


= tS?? of the Pb he- 


2 volts P D between stor- 


potentiiil, P I). 


cisely wliHt lilffercnre 




tween the plates of a 


age plates: 40 volts /' /» 


v=cxii- 


of level is with water. 




Clark cell at 15.5° C. 


between arc lamp jiosts ; 
10,00(1 volts for l-iri<h 
spark. 


Klcrtro - motivo 


The force which moves 


1 volt, E... 


= }SJJSoftheJEofaClark 


A gravity cell has I.l volt 


foico, K. 


electricity through a 




standard above = '^/^ 


E; an inc. lighting ily- 


E=CXH. 


conductor. 




of a Leclanche cell. 


namo has about l'^') 
volts. 


Current 


The time rate at which 


1 ampere __ 


= the r' which deposits 


^ ampere flows in a K'.- 


strenRth, C. 


e 1 e c t r i <• i t y Mows 




in 1 second I. lis 


candle power, 110- volt 


C^E^R. 


throuRh a comiuctor. 




nignis. of silver or 
other metal ei|uiva- 
lent. 
= Res. of a mercury 


lamp : 10 amperes in arc 
lani]). 


Hosistanco, TJ..- 


That property of a con- 


1 ohm 


1 mile trolley has 3 ohms; 


Ii = E-^C. 


ductor which opposes 


(true.) 


column 1 si|. mm. 


1,(KI0' cop. wire, 1 mil. 




the passage of elec- 




cross section and 10(i..3 


diam. has 1 ohm ; |ii- 




tricity. 




cms. long at 0° C. 


candli'iiower lamp (ila- 
nieiit hot, 200 ohms. 


Quiintitv, <? 


The total amount of 


1 conlomli _ 


= the (|uantity deliv- 


To deposit 1 pouml cojiper 


Q=CX T. 


eli'C t ri r i t y whicli 




ered liy 1 ampere in 1 


reijuires 1,500,01X1 con- 




flows in a given T 




second. 


lombs. 




(.seconds). 








Capacity, A' 


Measured l«y the Q re- 


1 farad 


= A' of container if 1 


1 microfarad = one- mil- 


A'= V-^E. 


([uired to nvise the 




coulomb raises its po- 


lionth of a farad = ca- 




container's potential 




tential 1 volt. 


pacity of I., mile ocean 




1 volt. 






cable. 


Work, ir 


The (iroduct of a force 


1 joule 


= 1 volt-con lomli ^ 


y2 ampere in llO-volt 


W -- K ■ U 


into a path ; also of 




work of 1 ampere 


lamp for 1 minute does 


cm r. 


(juantity into poten- 




through 1 ohm in 1 


3,300 joules; power = 




tial. 




8econd=().7373ft. Ills. 


55 watts; heat = 1,375 
calories. 


Power, /» 


The time mte of work. 


1 watt 


= P when 1 joule is 


1 kilowatt = 1,000 watts; 


/•= H'H-r. 


A horse pulling "5 




done uniformly in 1 


1 h o r 8 e p o w e r = 746 


( T in sees. ) 


llis. at 5 miles per 




second. Watts = 


watts ; 1 kilowatt = | 




hour exerts 1 horse- 




vol ts X 'I ni p e r e 8 = 


horsepower, approx. 




I" •"•<•••. 




amperes'' y ohms. 




Iloat, 11 


772.5.1 ft. Ills, work will 


1 calorie 


= 11 requireil to raise 


1 calorie = 4.1(5 joules = 3 


// = .24 /•; V 


niise 1 111. wati'r 1° F. 




1 gm. water 1° C. at 


ft. IIks.; 1 joule = o.24 


= .24r'«2r. 


at fi()° F., liOndon sea 
level. 




0° (\ = 1 gm. deg. C. 
= 0.004 lb. deg.F. 


calorie. 



1 inch = 2.54 centimeters. 
1 meter = 3.28 feet. 



1 megohm = 1 million 
1 micro. -■ 1 millionth. 



1 kilo = 
1 milli. 



1,000. 



(B) RUEES, EAWS, AXD EXAMPLES. 

I. — If a current shoidtl flow thrniufh the forefinger of the right hand, in the 
direction i)i n-hicti tlie finger jjoints. the nortJi end of a magnetic needle in the 
position of the tJnimh will jioint in the same direction as the thumb held perpen- 
diciilarh/ to the finger. (Figs. lSO-1.) 

II. — Ohms Law. — In ererif electrical circuit the strength of the current in 
am])cres flou-i)>g luiiformlij is etjual to the electro mot ire force of the generator 
in volts diriilcd hi/ the total resistance of the circuit in ohms. Or, C = E -h R. 

III. — The ilifference of potential between the ends of a conductor of a current 
(or the E. M. F. in itj equals the product of the strength of the current by the 
resistance of the conductor. Or, E = CR. 

(135) 



136 



HANDBOOK FOR ELECTRICIANS. 



IV. — The resistance of a conductor varies directly unth its specifi» resistance 
and length and inversely tvith its cross section or ivith the square of its diameter. 

V. — The resistance of two or more wires joined in series equals the sum of 
their separate resistances. 





180, and 181. Magnetic Whirlwind around a Current. 

VI. — The total resistance of two or more uires joined in parallel equcds the 
reciprocal of the sum of their separate reciprocals. 




R 



{f ohm between ^-1 and B. 



3 
Example. 

VII. — The electro-motive force of a battery is equal to the E of one cell midti- 
jilied by the number of cells in series. 

Ex. To find the E and R of four different batteries formed in turn from six 
gravity cells of 1 volt and 3 ohms each, connected up (1) all 
in parallel, (2) all in series, (3) three in series and two in 
parallel and (4) two in series and three in jjarallel, thus: 




iI'I'N'I'I 



B 






1 volt, Yo ohm. 



6 volts, 18 ohms. 



3 volts, 4^2 ohms. 



2 volts, 2 ohms. 



VIII. — To obtain the strongest current with a given number of cells through a 
given external resistance, arrange the cells in such a way that the internal resist- 
ance shall be as nearly equal as p>ossible to the external resistance. 

Ex. For an external R of 18 or more ohms, the six gravity cells above should 
be in series ; for 3 ohms external R, arrange cells two in series and three in ijar- 
allel, and so on. 

IX. — Each one of two or more parallel wires carries that part of the main cm- 
rent ivhich the reciprocal of its resistance bears to the sum of the reciprocals of 
all the resistances. 

Ex. A generator of 18 volts and 3 ohms, two leads of 1| and 3 ohms, and two 
branches of 4 and 2 ohms are connected, as shown. Find R's, C's, and ^'s. 

Resistance between A and i? = 1 -j- ( J + |_) = ^ ohm. Total 
R in circuit = A + 3 + 3 + f = 9 ohms. Main C = 18 -=- 9 = 2 
amperes. C in wire 4 = 2x (i-^f) =* ampere ; C in wire 2 
= 2 X (i-^f)=ii; sum of C's in both branches = 2 amperes. 

P D of. generator on open circuit = 18 volts; on closed cir- 
cuit = 2 X 6 or 18 — 2 X 3 = 12 volts. Of ^ = 18 volts of the ' ,^2. 
generatoi', 6 volts are used to overcome its own resistance, 6 
volts to maintain the 2-ampere current in lead 3, y volts in lead, If and f volts 
in the two branches. 

Ex. E R of branches 2, 3, 6 = 1 ohm. Total R = S ohms. C = 2 
amperes. C in branch 2 = 1 ampere, in 3 = f ampere, in 6, i ampere. 
Eight volts used in battery ; 4 volts in lead 2 ; 2 volts in branches 
and 2 volts in lead 1. Total, 16 volts. 

P D between ends of wire 2 = 1x2 = 2 volts. 
P D between ends of wire 3 = f X 3 = 2 volts. 

X. — The quantity of heat in calories produced in a conductor is equal to the 
continued product of yVjf, the square of the curreyit in amperes, the resistance 
of the conductor in ohms and the time in seconds. Or, H^ 0.^4- O'^ R T. 

Thus, 10 amperes flowing through a fuse of I ohm for 1 minute generates 
360 calories = 1.44 lb. deg. Fahr. Power = 25 watts. 



183. 



LAWS, WIRE TABLES, EXAMPLES. 



131 



XI. — The poiccr in xcattfi in any live wire or circuit equals the total volts 
mnltipVu'd bij the amperes or the square of the amperes times the ohms. Or, 
P=E (•= C'-' li. 

Ex. A storage battery of 55 cells in lii^htins; eighty llO-volt laini)s falls from 
112 volts on open circnit to 110, while the ammeter shows 40 amperes. How is 
the i)ower expendeilv 

^1/^s-..- In each lamp, 1 10 X A = 55 watts; in external circuit. 40- x 110 -=- 40 = 
4400 watts; in battery (112-110) 40 = 80 watts; in entire circnit, 112x40 = 
4480 watts. 

XII. — The (/rams. IT, of metal deposited, or gas freed, or electroli/te deeoni- 
posed hji C amperes in t sees, is W =0.0000 10.JS4 C T Z. Z is the chemical 
equivalent of the metal, etc. 

(C) AVIiaXG TABLE. 

1. Copper Wirino of U. S Underwriters. 

Coiiiputi'il fnmi — Wrinlit 1 nibic foot i-oppcr — mr> lbs., iiiiil resistance 1 mil. toot conimerciul soft copper, 
98^ pure, at 68° F. = 10.:JtJ7 international or true ohms. 





JS 




Ca^iacity. 


o 
V 




c 


■a 


3 








■^^ 




'/ 

^ 


i 

6 

II 


II . 

— s 


1^ 


S 
a'? 

s ■ 


II 

s ~ 


M 


1 
ll 


•3 


n 




y* 


^ 




E • 


B-J- 


J3 


K 


X 


B 


~ 




■- 




■- 


a^ 


e-S 


c 


■C 


■3 




g 




tL 


1 


t 


. o 


s o 

6^ 


E 


5 


3 


d 


c 




- 


" 


< 


» 


X 


^ 


p. 


fc 


^ 


"^ 




I. 


11. 


in. 


IV. 


V. 


VI. 


VII. 


VIII. 


IX. 


X. 




IX 


4il 


1,624 


5 


3 


6. 3880 


4.92 


18 




49 


Working formula 


17 


4."i 


2,048 


6 


4 


5. tH>60 


6.20 


21 




58 


for res. of / feet 


Hi 


r,\ 


2, 583 


8 


6 


4.0176 


7.82 


25 




65 


cop. of (/ mils. diam. 


l.T 




3, 257 


10 


8 


3. 18ti<l 


9.86 


31 




72 


.. 10.4 X I 


IJ 


• 14 


4, 106 


16 


12 


2. .5266 


12. 44 


38 




83 


Kes. increases 0.21 
per cent f(U' 1° V. 
rise of tempemture. 


i;i 




.5, 178 


19 


14 


2. oo;n 


15. 68 


43 






12 


81 


6, 530 


23 


17 


1.5890 


19.77 


48 


tii 


"169' 


11 


01 


8,234 


27 


21 


1. 2602 


24.93 


64 


4-17 


129 


10 


102 


10,380 


32 


25 


. 99948 


31.44 


80 


4-16 


134 


Res. H. D. cop- 





114 


13, 090 


39 


29 


. 79242 


39. 66 


97 


8-18 


148 


per = 1,0226 X soft 
cop. 

For actual cross- 


8 


128 


16,510 


46 


33 


. 62849 


49.99 


116 


8-17 


166 


7 


144 


20, 820 


56 


39 


. 49846 


63.03 


118 


8-16 


180 


6 


162 


2f., 250 


65 


48 


. 39528 


79. 49 


166 


16-18 


203 


sect ion nnilti|ilv 
Nos.in III Iiv0.7.><54. 


5 


182 


33, 100 


77 


53 


.31346 


100. 23 


196 


16-17 


220 


4 


2(M 


41,740 


92 


63 


. 24858 


126.40 


228 


16-16 


238 


Ft>r ohms per mile 


,3 


229 


.52,630 


110 


75 


. 19714 


159. 38 


265 


:i2-18 


259 


multiplv Nos. in VI 
by 5.28. 

Nos. in ^*I ffivt' 


2 


258 


66, .370 


131 


88 


. 166:}3 


200. 98 


296 


32-17 




1 


289 


83, 690 


156 


105 


. 12398 


253. 43 


329 


32-16 


'loo' 





•i25 


105, 600 


185 


125 


. 09827 


319.74 


421 


32-15 


:i40 


also volts fall of po- 
tential per aiiipeiv 
per 1,(MX» foot. 

Kroni III \vt' can 


(M) 


365 


Via, 100 


220 


150 


. 07797 


402. 97 


528 


32-14 


380 


(KX) 


410 


167, 800 


262 


181 


.06184 


508. 12 


643 


:J2-13 


425 


(KHKt 


460 


211,600 


312 


218 


. 049(H 


640. 73 


815 


32-12 


464 


Cables. 


630 


300, OOO 


405 


273 


. 03;W5 


932 




37-090 




get equivalent 
strand eable for jinv 


" 


727.3 


400, (H)0 


.503 


:j32 


.02516 


1242 


» 


37-1039 




" 


814.5 


50O, 000 


595 


390 


.02013 


1.553 


•c 


61-0905 




wire. Koui* No. IVs 


:: 


891.9 
963. 9 


600,000 
700,000 


(>82 
765 


440 

488 


.01666 
.014.38 


1863 
2174 




61-0991 
61-1071 




may replace one«>XXi 
wire Ijecause 4 "^ 


'• 


1030.5 


800, 000 


846 


54(» 


.012.58 


2474 


3 i 


61-1145 




5 2630 = II ea rl V 


" 


1092. 6 


900,000 


924 


585 


.01118 


2795 


S-s 


61-1214 




211600. For No. (>, 


" 


1152 


1,000,0<IO 


UKX) 


630 


.01IK)6 


3106 




61-128 




take two No. 3*f oi* 


" 


1208.7 


1, IlKt.lHHI 


1075 


675 


.IKItllS 


:«16 




61-1343 




four No. 6*fi. 


" 


1262.8 


1,2IK(. IKKI 


1147 


715 


.008:W 


:i727 


•S3 


91-1148 






" 


1314.5 


1,:«KI,(KKI 


1217 


7,55 


.O07t'i9 


4038 . 


^ "i 


91-1195 






" 


i:«H 


1,4IM),(M>() 


1287 


795 


.0(1715 


4348 


« ^ 


91-124 






" 


14i:i.5 


l,,5fKI, (HMI 


1356 


8.^5 


. (MI667 


4658 




91-1285 







" 


H.'iS. 6 


1,6(KI,(KI0 


142;} 


875 


.0062:1 


4968 


Z!5 


91-1326 






" 


15l«.7 


1,70<I,(KHI 


1489 


"910 


. 00588 


5278 


O -3 


91-1367 






" 


1.547. 7 


1,80(1, (HHl 


1.5.54 


946 


.(Ht.5.56 


5588 


|l 


127-1195 






" 


1571.9 


1,900,(K10 


1618 


980 


. (K».527 


5898 




127-1223 






" 


16.30.2 


2,000,0(K» 


1681 


1015 


. 00.5(,K) 


6208 


^ 


127-1254 







Rouijh rule. — One thousand feet of soft copper, one mil. in diameter (No. 10) 
has one ohm resistance at the ordinary temperature of a room. 



138 



HANDBOOK FOR ELECTRICIANS. 



2. Table for Taps, Bridge Wires, Etc., of Negligible Drop (0.15 of 1 

PER cent or less.) 








1 


2 


3 


i 


5 


6 


7 


8 


10 


12 


14 


16 


18 








300 
1280 


2G0 
108.5 


200 
860 


i60 
680 


130 

560 


100 
435 


80 
345 


65 

280 


50 
220 


38 
160 


24 
100 


15 
60 


9 
40 


6 


Feet |llO V ._ _. 


Vh 







3. Table of Sizes of Safety Fuses. 

Fuse wires should be stamped with 80 per cent of the maximum amperes 
which they can carry indefinitely, thus allowing i overload. 



Amperes carried , 
Diam. in mils 



% 1 2>^ 
17 2025 



60 73^ 
4045 



50 



70 



24 30 
100 110 



53 70 
160 180 



liio 
220 



In testing, allow naked open fuses five minutes to blow ; inclosed fuses not in 
contact, a shorter period. 



[D) GEXERAIi FORMUIjA. 



C=amperes. 

i2=ohms. 

£'=volts. 

Prr; watts. 

H P=horsepower. 
C P=candlepower 



?i=No. lamps in parallel. 
c=amperes in 1 lamp. 
e=volts in 1 lamp. 
/=feet on one side of circuit. 
f?=diameter of wire in mils. 
v= volts lost in wires. 



^'= motor efficiency. 
=ratio output to input. 
=0.75 in 1 h. p. motors. 
=0.80 in 5 h. p. motors. 
=0.90 in 10 h. p. motors. 
=0.95 in 50 h. p. motors. 



l_— Ohm's lmi\—C=E h- R; E=C R; R=E ^ C. 
2.—P=C- R=C E=E''^R. 1 i?P=P-- 746= C-^P^746. 

3. (a) Given the length, /, in feet and diameter, rf, in mils, of copper wire, to 
find its resistance at the same temperature ; R—l X 10.4 ^ (? -'. 

(5) Given the resistance, R', of copper or other pure metal at f ° F., to find 
its R at any other temperature f°F; R=R' [1+0.0021 {t—t'}]. 

Ex. From the table the R of 1,000' No. 13, at 68 F =2 ohms- at 60° F.=2 
(1_ 0.017) =1.97 ohms; at 100° F. =2. 13 ohms. 

4. Given the voltage and candlepower of an incandescent lamp to find the 
current strength to light it : c = C P X 3. 5 -f- (\ 

Ex. A 32-candlepower, 52-volt lamp requires, therefore 2.15 amperes. A 
16-candlepower, 110-volt lamp requires i ampere. 

5. To find the size of copper wire for feeders, mains, branches, service wires, 
or inside work to feed n, lamps in parallel taking each c amperes from a center of 
distribution distant / feet, so that the total drop in both wires will be v volts : 

7? X c X 2Z X 10.4, „ /-,!,. 1 ^ 
d- = — — — (from Ohm s law). 

With the value of d- found, look in column III of the table for the next higher 
value. If this wire has the carrying capacity in open (IV) or concealed (V) work, 
as the case may be, it is taken ; if not, the next larger wire. 

Ex. What gauge of copper wire will supply fifty 110-volt, 16 candlepower 
lamps at 150 feet distance from the center of distribution with only 3 volts loss? 

Ans.: e = 16 X 3.5-110 = 0.51 ampere, d' = 50 X 0.51 X 300 X 10.4--2 = 39780 
circular mils. , No. 4 B and S. 

6. Given the voltage e delivered to a lamp and the per cent drop {p as a whole 
number) in the wires of the voltage received to find the number of volts drop 
in the wires : 

v = p('^ (100— p). 

Ex. The leads to a cluster of 110-volt lamps are figured for a 4 per cent drop. 
What is the actual number of volts lost in the leadsV 

Ans.: V = 4 X 110 -- 96 = 4.6 volts. Voltage at supply end = 114.6. 

Ex. What size of wire will carry with a 2 per cent drop, 30 amperes, 200 feet 
to a 220 volt motor ? 

Ans.: v = 2X 220 H- 98 = 4.5 volts drop. d'= 30 X 400 X 10.4 -f- 4.5 = 27733, No. 
5 B and S. 

Ex. Conversely, to find the per cent drop in the wires when the volts drop 
and volts delivered are given : 

p- 100 r-i- (e + v). 



LAWS, WIRE TABLES, EXAMPLES. 



139 



ir 



Suppose there are 6 volts drop or loss in the leads to a 104-volt cluster or 
motor; the per cent drop in the leads = 100 X 6-^(104 + 6) = .'5.56 per cent. 

7. To find the volts loss in a given copper wire carrjing a given current : 

?' = ^, — : or multiply the number in column VI of the table by the 

feet and amperes and divide by 1,000. 

8. To find the sizes of feeder and mains in fig. 184, which give a drop or loss 
between feeder switch and the 32 16 candlepower lamps of 2 volts or less, lamp 
voltage to be as nearly uniform as possible. 

On the plan mark all centers of clusters and measure along the wires the dis- 
tances in feet between them. C is the heaviest main, having 10 X 33 = 3f?o lamp 
feet. Its 10 lamps are supplied over 33 feet 
of main and 1 00 feet of feeder. For a starter, 
consider at first the drops to be in propor- 
tion to the lengths, i. e., 0.5 volt in the 
main and 1.5 in the feeder. 

A 1.5- volt drop gives for the feeder 
</«= 32 X i X 200X10.4 ^1.5=22187, or No. 6 
wire. But No. 6 causes a drop of 1.3 volts 
either from (5) or from the proportion 
1.5 X il = 1.3, using in the fraction the first 
two figures only of (J- as approximate. 
Therefore, the drop in all mains will be fo 
volt or less. 

For main C. rr- = 10 X iX 66 X 10.4 -- 0.7 r^ 
4903. or No. 13. 

Likewise No. 13 is found for the main to 
the 8 lamps in ^l, 40 feet from center. 

No. 16 for B and No. 14 for D. Column 
T' shows all five wires to have sufficient car- 
rying capacity. 

For a check, use column VI, which gives 
the volts drop per ampere per 1.000 feet. 
For example, in feeder, drop = 0.395 (No. 0) 
X T'oVff (ft- ) X 16 (amperes) = 1.3 volts; in 
main C, drop = 2 x0.066 X 5 = 0.66 volt; in .4, 0.64; in B, 0.64; in D. 0.63. Be- 
tween i''Sand the ends of the four mains the losses are 1. 96, 1,94, 1. 94, and 1. 93 volts. 

If a problem gives the drop in per cent, find the volts from v = pe -r- (100 — j^) 
and proceed as above. In extensive wiring, tables computed from above 
formulas are used. 

Any tap off the main D, for in.stance, having a drop gi-eater than 0.07 volt 
would cause the total to exceed 2 volts. For this limit, one lamp at 50 feet dis- 
tance reciuires a No. 11 wire. But the sizes of tap wires may usually be taken 
from table page 138. 

9. To find (l- of copper required to transmit HP (horsepower), I feet, with v 
volts loss in the wires to a motor of e volts and k efficiency : 



T 



50- 



184. How to Find Sizes of Conductors. 



f/- = 



■ffPx 746 X2ZX 10.4 
t' X e X fc 



Then increase d '■ by 50 per cent for overloading and look in the table. 

Ex. A 110-volt hoist motor of 12 horsepower is 100 feet from the closet s^^^tch. 
Select the tap wires to allow only 4 volts drop from switch to motor whose effi- 
ciency is 90 per cent. 

Ann.: d-= 47020. Add 50 per cent and the wire is No. 1. 

10. The volts required for a constant current motor of i?" P (horsepower) and 
A- (efficiency) are, E = 746 xll P-^ C k: 

The amperes required for a constant potential motor of H P (horsepower) 
and k (efficiency) are. C = 746 xHJ'-i- Ek. 

Ex. The current to be supplied to a 220-volt motor of 90 per cent efficiency to 
get 12 hor.sepower is C = 746 X 12 -^ 220 X 0.90, or 45 amperes. 

11. Tlie insulation resistance of a wiring system, including dynamo, or of any 
jiart thereof, should be above 10,000,000 ohms, divided by the total amperes to 

flow in the circuit or in the part considered. Or, / R = — '—W — ohms. 

Ex. The IP of an 80-ampere installation is, then, 125,000; of a branch supply- 
ing ten 16-candlepower, 110-volt lamps is 2,000.000 ohms. 



140 HANDBOOK FOR ELECTRICIANS. 

12. To find the H P expended in a wire, HP=C- R^ 746. 

Ex. An arc light 10-ampere current flows in a 10-mile circuit of No. 6 B.and 
S. i? = 0.395X5. 28 X 10 = 20.8. The 77 P lost is 100 x 20.8 ^ 746 = 2.8. 

13. A storage battery, motor or arc lamp supplied by a generator E exerts a 
back electro-motive force e in the circuit. The effective E. M. F. is then E — e 

and the current, C — — ^^ — 

xt 

Ex. 1. Consider in simple circuit a dynamo of 8 volts and 0.02 ohm, a storage 
cell of 2 volts and 0.005 ohm, leads of 0.1 ohm and compute what ammeter and 
voltmeter should show. 

Ans. : C — S amperes ; drop-in leads = 0.8 volt ; PD between dynamo posts 3 — 
8 X 0.02 = 2.84 volts; PD between cell's posts = 2.84 — 0.8 = 2 04 volts = (for a 
check) 2 + 0.005 X 8. 

Ex. 2. What is the -E of a dynamo of 0.02 ohm supplying 100 amperes to 54 cells 
in series of 2.3 volts B. E. M. F. and 0.0004 ohm each, the leads having 0.03 ohm? 
Also P D's at dynamo and battery terminals? 

Ans.: E= (54 X 2.3) + 100 (0.02 -f 0.03 + 54 X 0.0004) = 131.4 volts. PZ)=129.4 
and 126.4. 

Ex. 3. A dynamo of 135 volts and 0.015 ohm was charging for seven hours 
through 0. 025 ohm leads, 53 cells each of 0. 0002 internal resistance and of 2. 1 volts 
at starting and 2.35 at end of run. Find B. E. M. F., current and regulator 
resistance to keep C at 200 amperes at starting and stopping. 

Ans.: At starting e = 111.3, = 460, R = 0.068; at end of run, e = 124.6, 
C = 206 P = 0.00165. 

Ex. 4. What must be the E of a dynamo of 0.02 ohm resistance in order to 
supply through 0.005 ohm leads, 7 brake ii"P to a motor of 90 volts back E. M. F., 
0.025 ohm internal resistance and 300 watts internal friction, etc. ".'' 

Ans.: C X 90-^ 300 X 746 .-. C = 61.4 amperes, £■ = 90 + 61.4 (0.02 + 0.005 + 
0.025)= 93.1 volts. If E of dynamo be raised to 95 volts, the motor will develop 
11.6 if P. 

Ex. 6. The 0. 11 ohm leads from a 50-volt P D source are carrying 10 amperes to 
an arc lamp of 39 volts, B E. M. F., which has 0.09 ohm in the lamp coil, 0.08 and 
0.12 ohm in the carbons and 0.1 ohm in the arc. What is the extra resistance 
which keeps the current in the lamp at 10 amperes? 

Ans.: Total P = ^^~^^ = 1.1 ohm. 1.1 — [0.11 + 0.09 + 0.08 + 0.12 + 0.10] = 
0.6 ohm. 



XVI.— ELECTRICAL MEASUREMENTS AND TESTS. 



The apparatus required in the order of iitility are: A portable Weston vcli- 
meter (150 — 8 volts) ; an inexpensive upright Weston, in a square hard- wood bos, 
having '^ at middle, movi'.ble coil of about (iO ohms, both a shunt and sei-ie5 
coil tc it such th;it two or three Leclanches will deflect the needle to tlie scale 
end with either, and connections permitting the use of the movable coil alone 
or with the shunt or series coil; a London P. O. bridge; a few fresh dry cells; 
a Weston milli-ammeter with shunts for heavy currents; and, if at hand, a 
storage battery and the switch board instruments. 

CARE IN HANDLING INSTRUMENTS. 

Do not send a current through a galvanometer, ammeter, or voltmeter with- 
out first knowing its direction, and rouglily its strength. Verify by striking 
with one of the galvanometer leads before closing for a reading. 

Clean metallic connections which scrape into contact are always made. 

Set down an instrument of any kind gently. 

If the needle is pivoted, taj) the case lightly before taking a reading — esi)ecially 
if the reading is small. 

The pointer should stand at zero when there is no current. 

A mirror beneath the pointer aids in getting a ])roper reading. To read, 
place the eye over the end of the pointer so that the pointer covers its reflection. 

When the box rheostat is u.sed, be sure that all plugs remaining in the box 
make such good connections as to cut out their coils. 

Turn the plug clockwise both in plugging and unplugging to keep the con- 
tact surfaces scraped, and never carry the plugs in the hand or lay them in a 
dusty place. 

If a galvanometer is not at hand, a telephone receiver or a telegraph relay 
may take its place in rough testing and the tongiie for continuity. 

A magneto series bell who.se capacity is known, is convenient and useful in 
continuity and in.sulation tests. 

Use a knife switch, not a contact key, to close a testing circuit. 

The current from a storage battery ought not to exceed 13 amperes per scjuare 
foot of positive plate surface, coiinting one side. 

The dynamo or battery which furnishes the testing current, must be well insu- 
lated and care be taken not to short-circuit the generator or to heat a testing coil. 

A Siemens detect(n" galvancnueter having a coarse and a tine AWre coil, although 
not so good as the Weston de.scribed, is more useful than a magneto in testing. 
For a cheap W. B., .string a G. S. wire of about 8 ohms uj) and down a hard wood 
board J3() inches long, on which bra.ss pieces are screwed as in fig. 187; for the 
third .side ])rocure a few coils of known R. 

I. — To inrdsiirc the strength C of a current. — Insert in the circuit an 
ammeter of sufficient capacity and of such low resistance as not to alter essen- 
tially the <iuant)ty to be measured. Good connections are specially recpiired. 

II. — To find the (lifferenee V of ))otential In'tween tiro (jiven points of an elec- 
tric cii'ciiif. — Hold tlae positive voltmeter lead on the higher ])oint and strike the 
other with the negative lead to verify the proper swing — both direction and 
amount — of th(> needle. Then hold the latter down and read. A liigh voltmeter 
resistance is required so as not to alter a])])reciably tlie (luantity to be measured. 

III. — To ti'st the eontinniti/ of d cirenit h;/ inemis of a detector 

golrinionieter and ii fen- cells. — Connect this apparatus in .series I 1 ® 

and strike terminals (piickly to see that all is in order. Then l pQ 

join terminals to tlio.se of the circuit under test. A deflection ^ < *• 

shows continuity. If there is no deflection i)roceed along the 
circuit touching across at convenient points with an extra wire 
until the 1)reak is reached. 

IV. — To nte((.snre a>i ordinary resistance R of a conductor 
re((dil!/ hi/ the Sidistitiition iiiettiod. — Connect the unknown A', 
a constant battery, a galvanometer (shunted if necessary) and ,^,5 Substitution 
a key in .series, and note the deflection. Take out A' and insert 

rheostat or G. S. wire from which throw into circuit a known re.sistance, ;• until 
the deflection is the same as before. Then, R = r. Small resistances in G and 
B and a lai'ge deflection of G are favorable conditions. 

(141) 



I 



142 



HANDBOOK FOR ELECTRICIANS. 



V. — To measure, an. ordinary resistance x of a conductor accurately with the 
Wheat stone bridge. — The Wheatstone bridge consists of three sets of known 
resistances, a. b and c, joined in series. They and the unknown resistance .r 
form (for a picture) the four sides of a diamond-shaped figure. A galvanometer 
joins any two opposite points of the diamond, and a battery the other two. Figs. 
186, 187, and 188 represent three forms, which are lettered to correspond. Two of 
the sides or sets, a and b, have usually three coils 
each, 10,100 and 1,000 ohms, as in the London P. O. 
pattern (fig. 188), or consists simply of a German 
silver or a platinoid bare wire, as in the wire bridge 
form, fig. 187. The third set or side has usually 16 
coils, so sized that any resistance expressed by a 
whole number between 1 and 11,111 ohms can be 
unplugged from it. Any resistance between jl^j 
and 1,111,000 ohms can be measured with the Lon- 
don W. B. , and two infinity plugs permits its use 
as three separate rheostats. 

To measure with a W. B. — Connect, as in figs. 
186-7-8, the unknown resistance .x\ with the three 
sets, o, b and e, of the bridge so as to form a 
simple closed circuit. There must be a certain 

amount of resistance in each set, the more nearly equal the better. Connect a 
sensitive galvanometer and key between any two junctions not adjacent and a 
battery and key between the other two junctions. 

While holding the battery key K^ down, depress (or better, strike) the gal- 
vanometer key K'i. If there is no deflection the bridge is balanced. If there is 
a deflection, alter the resistance in one or more of the three sides, usually c, imtil 
there is no deflection ; then the imknown resistance is equal to the resistance in 
c multiplied by that in b and divided by the resistance in o. Or x = cyib -i- a. 




186. Student Form. 



•CD- 





(""I 




i,\ \i> & i>\ Id) 




• 


,l,l,lil<l,l.lil.l.lilililili 


» 




a J^ i 





.A. 




187. Workshop. 



188. London P. O. 



VI. — To measure a targe resistance R like the insidation resistance of a con- 
ductor by means of a sensitive gatvanometer lohose constant or deflections are 
knou-n and a battery of known V. — Detach the conductor from all others and 
guard against leakage at its two ends over the insulation. Join in series either 
end of the conductor, G, V and the frame or ground plate as the case may be. 
From the deflection the current C through the circuit is knowni. Then, R — V 
-i- C — G'. G' is small enough, relatively as a rule, or can be made small by a 
shunt, to be called zero. 

VII. — To measure a small resistance R like a piece of cable, joint, armature 
coil, etc., by means of a Weston ammeter and voltmeter. — Connect up as in the 
^„ figure and read the deflections. Then R = E ^ C. 

[ I Ex. When a storage battery, a heavy rheostat to prevent 

|- * " ^" -y .short-circuiting, an ammeter and an armature whose resist- 
Li I I I o ' '^ ance was sought were joined in series the current was 15 am- 

I'ItH^ peres. The voltmeter (small coil) bridged across the two 

commutator bars in contact with the brushes showed 0. 09 volt. 
R of arrdature = 0.006 ohm. 

VIII. — To measure the conductor resistance R of the main or any feeder cir- 
cuit (lamps hot) by the switch-board voltmeter and ammeter. — Take the instru- 
mental readings while curi'ent flows in the circuit to be measured and compute 
from R^V -^C. 



189. By Volt and 
Ammeter. 



ELECTRICAL MEASUREMENTS AND TESTS. 143 

A conductivity test of a main or feeder circiait with a I) (V, or an R measure- 
ment by the substitution method, will preclude all danger from short circuit 
when the feeder switch is closed. 

IX. — Tf> iiicdsure an onlinitry resistance R by means of a H'l' 
voltmeter and a single Icnoii-a resistance r. — Connect as shown , 
(fig. 11)0). If the deflection is I'whenthe voltmeter leads are ^'* 
applied to the ends of A* and r when applied to r, R = r ^' -h r. I L_-y 
Large and nearly equal deflections for l' and v are favorable 190. Compari- 
conditions. son. 

X. — To measure a small resistance R by means of a voltmeter and a bare 
German-silver vire S of knon-n length and resistance. — Connect R. .S' and a few 

<? constant cells. Note the deflection T" of the voltmeter when 

j . ' s T its leads are applied to the ends of R. Next attach one lead 

' -I'l'l to the junction of R and S or the zero of the length of S. and 

'^'- slide the other lead along ,S' until the deflection is the same. 

-R= the resistance^ readily computed of that part of the German-silver wire between 
the two I'ontacts. 

Resistances between 1 olnn and 1 megohm are usually measii red by the W. B. ; 
behnv 1 ohm by the i)otential method ; above 1 megohm by the deflection method. 
But the substitution method being quick and approximate is often used for ordi- 
nary resistances. 

XI. — To locate a short or a partiallij open circuit (poor contact ) as in an 
annat lire by means of the roltmeter only. — bend a steady current through tlie 
armature by the brushes properly set. Apply the voltmeter terminals to 1 and 
2 commutator bars, then to 2 and 3 and so forth on one side of the brushes, and 
in like manner on the other. If the deflections are all eqiial there is no f)pen or 
short circuit. An increased deflection indicates a bad contact or unusual 
resistance ; a diminished deflection, a short circuit. 

Two or more magnet coils alike wound as on fields or a horseshoe, can be 
similarly examined by giving them the same current and comparing the poten- 
tials of the coils. 

XII. — To test a joint, stritch contact, battery connection, etc., by means of a 
voltmeter. — Let its maximum working current flow through it and apply the volt- 
meter leads to opposite sides of the joint, etc., and comi)are the deflection with 
that given by an equal length adjacent of wire or bar. If there is no deflection 
and the voltmeter is sensitive, there is no resistance. Joints in the same circuit 
may thus be compared and the loss of energy in them may be computed. 

If the current ( ' in amperes is known, the resistance in ohms of the joint, 
etc., can be found by R r= 1'-=- C. 

Ex. A foot of search-light main having a connection showed a difference of 
potential of ,'„ volt, and a foot of regular main showed ^\-, volt while carrying 
100 am-i)eres. The joint was a poor one. Its R = 0.001 ohm. Power lost in 
joint alone = 7 watts. 

XIII. — To measure a large R, as of insulation, by means of a u-ell-i7isulated 
dynamo or battery, and a We.'itoti tu-o-coil volttneter of r ohms ^. say 18,000 j in the 
larger coil. — Connect B, R and large coil of voltmeter, ;■ (fig. 192). If Tis the 

deflection Avhen the swntch is closed and v when it is open, R = r. 

V 

Ex. The deflection on a 20,000-ohm voltmeter closed on a dynamo was 100 volts, 
and in series with the dynamo and unknown R, was 40 volts. R = 
30000. pl'1,'1'1-]: 1 

Ex. The deflection by the lS,000-coil between the poles of a well- l_sk^Ji} 
insulated storage battery was 120, and by the ;3-volt coil between 
the extremities of the insulation R and battery joined in series was '92. 

^ volt. 7^=65 megohms. R in fig. 193 and in l)oth examples may be the insulation 
re.sistance of a cin-uit whose conductor is joine<l at ^l and a ground i)late to A". 

XIV. — To measure the R of a ground ou either leg of a jxtridlcl I>. ('. system 
by the abore method. — The comiections are made as shown for an uidvnown 



r J J J I gi-ound (m the upper main. Or, without the switch, tlie volt- 

^ ?^^ nil* meter leads may be applied first to both mains to get I ' and then 

^ ^ to the lower main and ground to get c; whence, 7v' =( T' — v) 

r -=- /' ohms insulation of ui)per side. The operation is similar 

193. foj. fi,i,ii,,nr ^^ii,> amount of ground on the other or lower side. 

Ex. The 19,000-ohm voltmeter gave 124 volts between d>niamo In-ushes and 

4 volts between one main and ground. The insulation ji of the other main 

= (124 — 4) 19000 -^ 4 = 570000. 

If the insulation on one leg is R and ou the other R', the insulation of the 



system is l^(i + ^,). 



_5^ 



144 HANDBOOK FOR ELECTRICIANS. 

Ex. The insulation on the other main in the above example was 300,000 ohms. 
The system's insulation = 200000. 

If no deflection shows between a main and one ground there is no ground on 
the other main. But if the deflection equals that between mains, v = V R~ O, 
tlie fault on the other is a dead ground. 

Every properly-arranged switch board pewnits the insulation on either side to be 
quickly taken of the whole system, or of any feeder circuit, or of the dynamo 
alone. 

XV. — To measure the insulation R of the d/jnaiito alone, the operation is simi- 
lar after opening the main switch. If no deflection of a switchboard, Weston 
18,000-ohm voltmeter between one side and ground is percejitible, say ^V volt 
while the dynamo is running at 110 volts, the insulation of the other side 
must exceed from XIII, 18000 X 110 X 20 = 40 megohms. 

XVI. — To measure the internal resistance R of a dynamo or storage battery 
by means of a Weston voltmeter and ammeter as at the switch board. — Take the 
potential T" of the generator on open circuit, and again the potential v when 
closed on as many lamps as convenient, and at the same time read the current 
C of the ammeter. R = ( T" — r) -^ C 

Ex. The IIG volts of 58 storage cells on open circuit fell to 115 volts when 
closed on 40 lamps and the ammeter read 20. R of battery = ^}g ohm. 

XVII. — To measure the internal R of a battery, with a voltmeter and a knotim 

r. — Connect as in fig. 194. Suppose Fis the deflection when the 

T'— t' ' ' ' 

switch is open, and v when it is closed, R= — -; — r ohms. 

Ex. Three Leclanche cells in series when connected directly 
to the 5-volt coil showed 4.5 volts, and when shunted by 4 ohms W\A/VVWW\p3i 
showed 3 volts. R of battery = 2 ohms. 

For a large storage battery a heavy current rheostat and the 
larger voltmeter coil would be necessary. 

XVIII. — To measure the internal resistance R of a battery 194. 

readily by means of a low, resistance galvanometer G, and a 
rheostat r. — Join R, G and r (well plugged) in series and note the deflection 
which should be made small by shunting G, if necessary. Next unplug r ohms 
from the rheostat until the deflection is halved. Then, R = l r. Close the bat- 
tery for as brief a time as possible that its R may not change. 

XIX. — To measure the resistance R of a galvanometer readily by means of a 
loH'-resistance battery and a knoum r. — Join R, B, and r well plugged in series; 
note the deflection which should be small by arranging the cells of B in parallel, 
if necessary ; unplug /■ ohms until the deflection is halved. Then, R = \ r ohms. 
The R of a galvanometer is preferably measured as an ordinary resistance. 

XX. — To test the insulation R of a conductor by means of a magneto. — 
Detach the conductor from the rest of the circuit. Join one terminal of the 
bell to the conductor and the other terminal to the gromid, frame of instru- 
ment, dynamo, etc., from which the conductor shoiald be insulated. If the bell 
rings feebly on turning the crank the insulation resistance is less than 25,000 
ohms, or the capacity of magneto. If not, the insulation is greater, 

XXI. — To select and label the conductors of a cable. — At one end connect any 
conductor (insulated from the others) to the sheathing ; at the other end connect 
the sheathing, a few cells, and a detector terminal in series ; tap rapidly with 
the other terminal each conductor's end in turn until a deflection is obtained. 
Tag this end and the other connected with the sheathing as wire "No. 1." In 
like manner find No. 2, and so on. 

A telephone receiver and a cell, or a magneto and bell, may be used in place 
of the above and a separate wire in place of the sheathing. Conductors can 
likewise be selected at the middle without cutting by piercing the insulation 
with an ordinary fine needle, which is made the terminal of the detector. 

XXII. — To test for crosses, grounds, and insulation of conductors in a. cable. — 
Dry both ends of the cable; separate No. 1 for the test from the others at both 
ends ; at the near end, bunch the others to the sheathing and connect the Imnch 
in series with two or three cells and a telephone receiver post. When an insii- 
lated wire from the other receiver post is tapped qxiickly on No. 1, if well insu- 
lated, a click will be heard from a charge flowing to the wire, but not at the 
second or third succeeding tap. But if No. 1 is crossed or grounded the click 
will be alike for all taps. Having properly labeled No. 1, repeat the operation 
on No 2 withdrawn from the bunch, and so on. 



XVII.— SPECIFICATIONS FOR REQUISITIONS, ALTERATIONS 

AND REPAIRS. 



IX GENKRATj. 



Every electric machine or piece of apparatus for war iises shall he simple, 
certain" in operation, proved in the industries to he standard in its class and sup- 
plied by ons of the leading manufactories in the United States. 

(A) POWER HOUSE. 

1. Located centrallv and 3 feet from protectinc: earth traverse or emhank- 
ment: built of brick or old fortification granite : floored with concrete; roofed 
with slate and iron in shed form or with low middle ridge; supplied with at 
leas" five large, removable windows on three sides and with three large, window- 
paneled doors on the front. In the rare cases where the power house can not be 
protected, the machinery will occupy outer and sun-lighted rooms only, of the 
work. , ^ , ^, 

•J Partitioned laterallv into ((/) boiler, (b) generator. {<■) battery rooms. 

[u] holds an inclosed coal bin for three days' supply, with outside chute at top 
and an inside shovel hole at the liottom accessible from furnace door. Large 
plants have separate coal rooms. Door permits horizontal tubes to be with- 
drawn. There is a ventilator at the highest point. For oil engines (a) holds 
water tank, oil and supplies. 

(/») affords at least 4 feet clear space around engine. and d\niamo and m front 
of switch board facing dvnamo. Door between (a) and (b). 

(c) contains two battery stands of two tiers or shelves each, solidly built from 
one-size material (see 'Storage liattery "). They extend along the lateral walls 
and iiave o feet clear space between them, or preferably 30 inches or more clear 
apace on l)oth sides. Distance between shelves = 2 X height of jars. Ventilators 
at top and bottom. 

(IJ) BOIT^ERS. 

A boiler is rated at 1 horsepower, which, with easy firing, moderate draft, 
ordinary fuel, and good economv, can evaporate per hour 30 pounds (about i 
cubic foot ) of water at 100° F. into steam under 70 pounds pressure above the 

atmosphere. , ■, ■, n ^ ■ ^ ^■ 

1. For 85 horsepower or less, procure from the standard factories only, verti- 
cal fire tube ; for larger power or as space permits, vertical or Hor. retuni fire 
tube without dome; working pressure = 100 pounds; water test = 150 pounds ; 
safety factor = 5; recpiirements in practice in chapter I. 

2 Tlie shell is of mild, nontempering, open-hearth steel plate, f to f inch 
thick, having G0,000 pounds tensile strength, 5« per cent ductility, 20 per cent 
elongation of a piece 10 by 2 inclies wide. This data and firm name are stamped 
on each plate. All holes are bored, not punched; all joints, lapped and double- 
riveted longitudinallv and single-riveted laterally. 

The tubes of cold-drawn, .seamh'ss steel, 2-inch diameter in vertical boilers, 3- 
inch in horizontal and at least ^ inch thick, closely fit holes drilled ^ diameter 
apart in the clear ; the ends are expanded and flared. 

3. Length, one and three-fourths to two and one-eighth times diameter; 
capacity = one-third gi-eater than maximum required by engine; 12 square feet 
heating' surface per horsepower if boiler is vertical ; 15 sciuare feet, if horizontal ; 
3(5 square feet heating surface per s(iuare foot grate; one-third to one half of 
grate per horsepower ; total tube opening, one-tenth to one-seventh of grate area ; 
"grate air passage = one-fourth to one-half grate area : cliimney cross section = 
one-fifth of tube opening ; water feed = 1 to 1 i inch diameter ; blow-off = 2 to 2^^ 
inch diameter; steam feed = engine opening. 

4 Interior braces and stavs of steel of (50.000 pounds, T. S., not welded nor 
worked in tb." firt". riveted jind bolted, shall have such cross section that the 
1711— lit (145) 



146 HANDBOOK FOR ELECTRICIANS. 

strain ( = boiler pressure X area braced -=- cross section) shall be same as T. S. 
above with same safety factor and firm-name stamp. Openings, 2 inches or larger 
in the shell, shall be flanged. Manholes or hand -holes at bottom and top shall 
permit thorough inspection and cleaning. All seams are calked inside and out. 
Fire door has air inlet. Safety plug in tube is 2 inches below lower gaiige and 
near a hand-hole. 

5. Fittings, except pipes, are brass. 

(a) All piping, wrought iron or steel, are direct and short, with few bends 
which must have large radii, and will be laid so as not to allow water to stand 
in them. Steam pipes rise slightly toward the shut-off valve next the boiler. 
Boiler and steam piping are covered with asbestos. No piping is embedded in 
concrete. 

(b) Muffled pop safety valve, with lifting handle, has 1 square inch aperture 
to 3 square feet grate, and opens at 5 pounds above working pressure. 

(c) Steam gauge, 6-inch face, has siphon and air cock. 

(d) Three water-gauge cocks. Lowest is 2 inches above upper horizontal 
tubes, or one-third of the distance between lower and upper flue sheets. 

(e) Glass gauge, with two cut-off valves, drain cocks, guards, and extra glasses. 
(/) Blow-off valves, with screw motion. Scum blow-off cock. 

(g) Injector, lifting, lies direct as possible between supply and the delivery 
above crown sheet. Delivery tube is so bent that water entering will flow with 
the circulation. Has both check valve and stopcock. 

(h) Double-acting suction and force pump has air chamber, a branch in 
suction for boiler compound and an independent and straight connection. 

(i) Feed water, heater and purifier. 

(j) Steam separator. 

(k) Exhaust directible into smokestack. 

(C) generati:n"G set 

1. Is either a (1) standard, direct-connected, simple, steam engine and dynamo 
on a common iron bed plate effectively grounded, or (2) a Hornsby-Akroyd 
oil engine, link-belt connected with a standard dynamo on wooden base and 
having an inertia wheel. 

(a) Siipplied by General Electric, Westinghouse, or like standard company. 

(b) Stamped with name, volts, amperes, power, speed, -+- and — posts, N. and 
S. poles. 

(c) Located with switchboard in a dry, ventilated, sun-lighted room used for 
no other purpose, and kept dry by an oil stove if subject to dampness. 

(rf) Bolted to concrete foundations of dimensions given by the makers. 
(e) Tested for two hours on one-third excess of its full rated load without 
injury. 

(/) Capable of long runs on full load without undue heat or wear. 

(g) Perfectly balanced and runs true without vibration, noise or leaks. 

(h) So efficient as to give by ammeter and voltmeter 0.80 of indicator's power, 

2. It requires : 

(a) A competent and devoted attendant. 

(b) At least 4 feet surrounding clear floor space. 

(c) Large windows on two sides. 

(d) Full sets of tools, oilers, standard spare parts. 

(e) Full working tracings and diagrams. 

(/) If large, two or more like units with one spare. 

((/) W. P. cover when not in u.se. 

(h) Self -oiling of all bearing surfaces. 

(t) Means to recover surplus oil. 

(,/) Guards to stop oil being thrown. 

(k) Metal can for oily waste. 

(1) That oil shall not run along shafts or spill. 

3. (a) Engine, high-speed, double-acting, automatic cut-off, simple, vertical, 
if 30-horsepower or less, horizontal if larger, compound if very large ; to work 
most economically on 80 pounds pressure if simple, on 100 pounds if compound; 
to allow, with economy, a variation of 20 pounds either way and fulfill condi- 
tions on page 47. 

(5) The piston, rods, crosshead, guides, shaft, nuts, bolts, of the best forged 
steel, are accessible for repair, capable of realignment when worn and strong 
enough to allow sudden throwing on and off of the whole load. The cj^linder 
and valve chest, of cast iron encased with nonconductor, have relief valves 
removable for indicator connections. 



SPECIFICATIONS FOR REQUISITIONS, ETC. 



147 



(c) At full pressure the governor prevents a variation less than 2* per cent in 
the numljer of revolutions during a change from full load to one-fifth thereof, 
and less than o yvr cent for a change of both steam pressure within limits given 
above and of full load to no load. 

((I) The engine will have cylinder, ui)-feed lubricator, aiitomatic sight-lubri- 
cation elsewhere, oil collectors and guards. The exhau.st, directible to smoke- 
stack and led out.side and concealed, should be killed if flowing water is available. 

{(') Ideal, Ball, Straight Line, Mclntosli and Seymour, Armington and Sims, 
and Westinghouse are names of good engines. 

4. The dynamo is direct current, multipolar, compound-wound, and has suffi- 
cient potential to maintain during full load and normal speed, 110 volts at the 
farthest lamj), and to charge 58 storage cells. 

(^0 It requires: 

A ventilated, balanced armature: a laminated core of soft -iron disc rings; 
P. D. between adjacent bars less than 10 volts; two or more brush carbons in 
each .set; rocker locked in any i)osition ; large self aligning and oiling bearings; 
field frame in upper and lower halves; fuses on both leads; equal magnetic 
pull by all poles; all circuits of 0.99 cond. of pure cop. ; a field rheostat by 
same builder. 

(h) It is capable of ruiming eight hours on full load, or three hours on 15 per 
cent overload, withinit heating tlie c'ommutator 50° F. or any other ]iart •)() F 
above tlie surrounding air as given by 
a thermometer placed (in first case) on 
the heated jiart and covered with 
waste, and in the second case, 3 feet 
from dynamo in line with the shaft. 

(c) A change from full load to no 
load, with bru.shes and rheostat fixed, 
causes less than 2 i)er cent variation of 
potential and no sparking. If the full 
load is suddenly thrown off, the swing 
of a Weston voltmeter from self- 
induction is less than 10 volts. 

((/) Noinsulating part can be injured 
liy moisture or 200 ' F. rise of tempera- 
ture, and tlie insulation between cir- 
cuits or between entire circuit and 
iron frame exceeds 1 megohm tinder 
1,000 A. C. volt test both before and 
after a run. 

((') Armature windings must be 
symmetrical, systenuitic and replace- 
able; end connections, short and 
mechanically made to bars ; wires hav- 
ing wide P. D. are kept apart ; no wires 

cross in contact with eacli other. .„^ c- i^ r.i. ^ * «, 

195. Field Rheostat, W-e. 

(D) SWITCHBOARDS. 

Switchboards, preferably of slate, must not carry anything which is com- 
bustible or absorptive. 

Be free from moisture, dust and accessible from all sides. 

Have a main switch, main cut-out and ammeter for each generator ; a D. P. 
switch and cut-out for each circuit leading from lioard and a voltmeter and 
ground detector. 

Meet all requirements of pages 56-7-8. 

Be wired as sufficiently indicated on page 74. 

(E) STORAGE liATTERV (RESERVE EXCEIT FOR MOTORS 
AX1> SEARCH EIGHTS). 

1. Fifty-eight chloride .storage cells of about 1 sqiiare fo<it positive plate (one 
side) per 12 amperes of normal charging and discharging rate for eiglit hours 
should show s.-) per cent efficiency and cDnform with requirements in VI. 

2. The glass jars rest on sand in wooden trays on glass or porcelain insulators 
on shelves of paraffined solid framework. 

3. Lead-lined strong wooden tanks are used when plates exceed li square feet 




148 HANDBOOK FOR ELECTRICIANS. 

4. Connections are lead-bnrnecl, if practicable, or so bolted that they allow no 
greater drop than an equal length of lead lug. 

5. The jars, readily accessible on two sides if possible, should stand free from 
concussion and the direct rays of the sun. 

6. Fully protected by an overload automatic cut-out and a D. P. switch near it. 

7. Supplied with meters and facilities enumerated in VI and XII as necessary 
for the care of batteries. 

(F) ELECTRIC MOTORS. 

1. All electric motors should be — 

Furnished by one of the leading manufactories in the United States. 

Guaranteed to meet the general requirements given above for dynamos. 

Located in a clean, dry, well-lighted place under oilcloth cover. 

Insulated by moisture-proof wooden base frame if possible ; else dead-grounded. 

Slotted ring armature ; brush holder capable of fine adjustment and fixable in 
the proper position. 

Series wound (if hoist), multipolar and having 50 per cent excess of power. 

If required, inclosed by frame against damp and dust. Hand-holes have covers. 

Supplied with radial carbon brushes, two or more in each holder. 

Constructed so as not to sjiark between no load and 15 per cent overload. 

Fed direct through exclusive feeders having a cross-section to carry 50 per 
cent excess of current. 

Protected by rheostat, overload and underload circuit-breakers, fuses and D. P. 
knife-switch within sight of motor. 

2. Rheostats to motors constructed of fire and moisture proof material by the 
builders of the motors, have the overload and underload releases, usually attached, 
sufficient caijacity without paralleling coils and 1 megohm insulation R. The 
contacts should be ample, the resistance such as to drop the full potential 80 per 
cent at the first point. Capacity and factory No. are plainly marked. There 
are three types : 

(a) Starting, capable of carrying line voltage 15 seconds. 

(b) Regulating, capable of carrying full line voltage indefinitely. 

(c) Regxilating and reversing. C through armature only is reversed. All 
springs are of bronze and carry no C. Points of control are clearly indicated. 
Rheostats in damp positions are inclosed by a water-tight, fire-proof case. 

(G) SEARCH LIGHTS. 

1. The brass projector, painted dead black inside and out, holds the parabolic 
glass mirror, 36 to 60 inches in diameter, J to i inch thick, and is mounted upon 
a low platform of a four-wheel tru.ck. Its arc can be supplied at 1,000 feet dis- 
tance from the dynamo through double cable. 

2. The projector can be directed by hand or by means of a controller, multiple 
cable and two shunt motors, so that the beam can be turned to any desired point 
by a person 150 feet away from the projector, right or left, up or down, in agree- 
ment with like motions of the controller's single handle, and with a rapidity 
depending upon the amount of throw of the handle, or with as small motion as 
desired. 

3. The drum must be evenly balanced, well ventilated, and fitted with peep- 
holes for watching and hand-holes for adjusting the arc. 

4. In all the means of operation, in excellence of workmanship, and photo- 
metric power, all projectors must equal or excel the Schukert and Q-eneral Elec- 
tric search lights of like size manufactured for the United States Government in 
1900, as given on pages 90-103 of the Handbook. 

(H) IN^CAISTDESCEISTT LAMPS. 

1. Sixteen-candlepower lamps, with Edison short base, screw into a brass out- 
let box closed by a glass, screw-rim globe (fig. 199) for ordinary use. For pow- 
der magazines, 33-candlepower lamps are clustered inside an air-tight, moisture 
and fire proof lantern which is i)laced in the end wall nearest the gallery and 
furnished with reflector and diffusing lens. 

2. All lamps are 110-volt, and of standard size and make. Efficiency = 1 candle 
per 3.1 to 3.5 watts; ireeful life = 800 hours; appoi'tion one 16-candlepower 
lamp to 1,000 cubic feet room space. 

8. Filaments should stand centrally in a uniformly molded lead glass bulb 
without tip, have two or three curls without anchor, and show no dark or bright 
spot when heated to a dull red. The vacuum should allow no glow when tested 
on an induction coil delivering a |-inch spark. 



SPECIFICATIONS FOR REQUISITIONS, ETC. 



149 



4. The mean horizontal candlepower obtained by revolving the lainj) in a ver- 
tical jiosition ISO times per minnte shonkl be -within 1 candlepower of its rating, 
and shoiald not fall below 80 per cent of tlie initial candlepower after 800 hours' use. 

0. Sockets of bra.ss, never less than 0.013 inch thick, have .solid construction, 
standard screw threads, porcelain base, insulating lining fixed, tough and fire- 
proof, and ])oints of opposite polarity at least /4- inch apart, unless separated by 
reliable insulation. Except in special cases, they are keyless. If suspended, the 
flexible cord enters the socket through strong in.snlatlng biishing, i inch inside 
diameter. 

(1) AVIRIXG. 

1. The closet system of two- wire parallel distribution of direct current to 
lamps, motors, search lights, storage batteries, detonators, etc., afford thel)etter 
control and protection, whether or not the wiring is jjartially overhead or 
underground, or wholly interior. It takes more wire tlian tlie tree system, 1)ut 
allows switches and cut-outs to be safely and conveniently grouped and lamps 
to be at more nearly equal voltage. 




196. Distributing Current to Centers. 

(a) Feeders run from bus bars to main centers in slate closets or to motors; 
mains, frona main centers to cut-out boxes (sub-centers) : branches, from cut- 
outs to ]>laces to be lighted, 12 or less lamps; taps, from branches to lamps. 

(?>) The route to a lamp is : (1) Busbar, (2) D. P. knife switch, (3) fuses to 
protect feeder, (4) feeder, (5) bus bar main center distributicm box, (0) baby 
D. P. knife s\\ntch, (7) fuse to protect the main, (8) main, (9) inclosed fuse of 
cut-oi¥ box to protect the branch, (10) branch, (11) tap to outlet, (12) snap 
switch, (13) lamps. 

(c) Search liglit, motor, or storage battery has its exclusive feeder. 

2. Safety fu.se cut-outs are ])laced in full view at centers and subcenters of 
distril)ution, or where a smaller wire begins in a parallel system, or where a 
motor, battery, etc., requires protection from OA^erload and inside a biiilding 
where wires enter. 

Safety fuse cut-outs are D. P. and mounted on insulating bases in a small 
dust, moisture and fire proof box. held out from walls on porcelains. Fxise- 
wires are in contact only with their connections and are finch long for oO volts, 
1 inch for 110, to prevent arcing. 

Cut-outs require coi)]:)er tips stamped with maker's initials and 80 per cent of 
the maximum C which the fuse will carry indefinitely, thus allowing one- 
fourth overload. 

Any set of lamps reqiiiring more than 660 watts .should be dependent upon 
UKire than one cut-out between the lamps and dynamo. 

Cut-outs and circuit-breakers are to protect and switches are to disconnect all 
circuits beyond them. 

3. M.tgiietic circuit-breakers protect automatically djniamos, motors and bat- 
teries against overload with more certainty than fuses, also against underload. 
Both kinds must operate with excess of power and within 5 per cent of adjust- 
ment. Overloads are usually set to open the circuit at one-half excess of cur- 
rent or one-fourth excess of voltage; underloads, to open at 5 or 10 amperes of 
current, or at one-fourth fall, if voltage. Tliey must meet tlie re<iuirements on 
jiage 61 of Ite C. B's. (inverse time element). Magnet iron parts are copper- 
plated. 



150 



HANDBOOK FOR ELECTRICIANS. 



4. Switches and circuit-breakers are — 

(a) Mounted on small slate, porcelain, or marble bases, or preferably on the 
switchboard when used there, make sliding and secure contacts, make and 
bi'eak raj^idly without stop or spark. 

Carbon-tipped and have threaded studs and flanged nuts to make back con ■ 
nections. 

Stamped with words "on" and "off," maker's name, and maximum C or V. 




197. Cabinet Panel; Six Double Branches, Six F. S., One M. S. 

(h) All conducting parts have such cross-section that heating from maximum 
C can not be felt by the hand. 

(c) All switches are double pole; snap for 10 amperes or less; knife for larger 
but not smaller than 50 amperes ; in conduit not at centers, snap switches, 
marine type, to 50 amperes may be used. 

{(I) Switches and cut-outs are located, and whenever possible grouped, inside a 
fire and water proof insulated box centrally located in a dry, accessible place 
which is free from inflammable material. 



I ' 



198. Cabinet Panel, Six Single Branches, at a Center. 

5. General rules for toires. — (1) Coils purchased must show name of manu- 
facturing comjiany, date of manufacture, maximum voltage, and a guarantee 
to be "National Electrical Code standard." 

(2) All conductors are No. 14 B. and S., single, and above that size in strand 
of 7, 19, 37, 61, 91, or 127 wires of one size— No. 19, 18, 17, 16, 15, or 14. One of 
a strand lies in the center, and others, in layers, are twisted uniformly around 
it, one turn in 20 or 30 inches, adjacent layers being wound in opposite directions. 

(3) Copper is tinned. No variation 'of diameter greater than 0.002 inch 
allowed. 

(4) On poles~H. D. copper with R. C. and W. P. insulation or bare aluminum. 
In conduit, ducts or on cleats — soft copper of 98 per cent condxictivity of pure cop- 
per, coated with rubber and its compounds to a total thickness of i-^ inch on No. 14, 
increasing with larger sizes to |-inch thickness on wire of 1 , 000, 000 cm. or larger. 

(5) For all rubber-covered single conductors: (a) First layers are of 98 per 
cent pure para rubber, toiTgh, elastic, at least 4j "^^^^^ thick for all sizes, and 
without flaws. 



SPECIFICATIONS FOR REQUISITIONS, ETC. 



151 



f7>) Npxt layers are viilcanized niljber of 40 per cent i)ure Para, smooth, con- 
centric, coutinnous. at least 57 inch thick on No. 14 increasing' to ,."4 inch on wnre 
of 1,0(10,000 c. m., and without lioles or flaws. 

(0 All layers of cotton tape thoroughly impregnated with rubber coin]»()und, 
lap tightly one-half of the width into an even circular section at least .,'._, inch tliick. 

{(l) All exterior braid is closely woven and thoroughly saturated witli an insu- 
lating water-proi)f compound, unin.inredby 200° F. dry heat, ])ending, or alirasion. 

(6) Finished R. C. wires must show an insulation greater tlian 100 megohms 
per mile during thirty days' immersion at 70 F; also a dielectric strength such 
that 1 toot, after seventy-two liours' immer.sion, willresist for five minutes 3,000 
volts A. C. per ,,'f inch thickness of rubber. 

(7) When a cable has two or more conductors, each is insulated A\nth rubl)er 
and taped. Then all are twisted, usually in layers, around the central wire, the 
interstices often filled with jute, and the resulting cylinder istai)edandslieatlied. 

6. Interior coiHliiit. — (I) All interior wiring is drawn, for jirotection against 
moisture and injury, into low steel conduit, i inch to 2i inches inside diameter, 
enameleil outside* and inside and •'dead-grounded." 

('2) Its lengths are coupled together like gas pipe and screwed into bronze 
.iunction, closet, switch and outlet boxes having close-fitting doors or covers 
which are screwed home on rub])er gaskets. All ends of pipe are sealed up. 
The lamp outlet box is closed by a glass globe over the lamp, 
Bcrewing against a ga.sket (fig. 199). 

(3) To the bottoms of all boxes is screwed a slate panel, or 
marble board, or porcelain block, which carries and insulates 
the switch, fuse, or .socket. 

(4) Tlie condi;it is either strapped to asphalt-painted wooden 
cleats, '6 feet apart, so as to run with all of its boxes 1^ inches 
out from ceilings or walls, or it is embedded in the concrete 
2 inches from the surface of wall or ceiling. Its boxes lie on 
the surface in the latter case. 

( .-) ) The former or exposed conduit can be painted, repaired, 
altered, and kept air and water tight. 

(0) A good coniluit system is rigid, continuous, and prac- 
tically air and moisture tight throughout. 

(7) Rounded insulated cajiping to the ends of pipe in.side 
of l)oxes i)revtints abrasion of the wire. 

(8) Great force in drawing in wires is unnecessary and 
may cause leakage. 

(9) Both ])ositive and negative legs lie in one conduit 

where either has less than 80.000 c. m. conductor; if larger, each has a separate 
conduit. Clearance is ^V inch at least. 

{ 10) Conduit wires recpiire ^V inch thickne.ss extra fibrous covering. 

(11) Every length of 
good conduit isstamjjcd 
with makers name. 

( 12) Snap switches, 
being easily boxed, may 
be used with conduit to 
1 2 am])eres. 

(1 3) D.P.knife switches 
are i)ut m center of dis- 
tribution closets. 

(14) Wires are never 
' ■ fi.shed " in forts. Flex- 
iltle iron armored con- 
<luit is i)ermitted for re- 
pairs and "droj) cords." 

(15) Conduit is in- 
.stalled and all con.struc- 
tionfinislied before wires 
aredrawnin. Bendshave 
4 inclies radius at least. 

(1(1) After tlu' wires 200. Exterior, Wire Conduit in Forts. 

are drawn in the ends of exposed conduit and outlets are sealed, all joints of 
pipe and boxes art> painted with asphalt and i)recautions are taken to keep the 
interior air tight. 

7. lJn(ltrfiri>ii)i(l liiii'n. — (1) Exterior electric wires will, as a rul(\ li • below 
frost, often 4 feet underground, by being drawn into wrought-iron pipe or glazed 




199. Waier=tiKhi 

Outlet Box and 

Ulass Cilobe. 




153 



HANDBOOK FOR ELECTRICIANS. 



i 



clay conduit set in concrete. Both of these ducts connect manholes about 250 

feet apai"t and will last indefinitely. 

(2) Wrought-iron pipe duct (figs. 201-3), in 20-foot lengths, of 3 to 4 inches 

diameter, i inch thick, dipped in tar to prevent rust, are jointed by a screw 

coupling, so as to be water and gas tight. The concrete is composed of 1 part 

RosenTiale cement by volume, 2 parts sand, 
■'"."H"!,''!,""" ^nd 34- parts of Ijroken stone 'passing 14 -inch 

mesh ; is first laid between 14-inch planks on 
the smootli bottom of the track and rammed 
to 14-inch thickness. UiJon this is placed 
the first layer of pipe, 1 inch apart, and (-on- 
crete is rammed between them and above to 
14 -inch thickness. The process is repeated 
until the section is completed with a 2-inch 
plank cover. At a bend a manhole is built 
or the curve is given a large radius. 

(3) Glazed clay conduit 18 inches long, 3- 
inch bore, with walls | inch thick and out- 
side corners rounded, are laid, breaking joints 
as in fig. 202. There is 4-inch space between 
the pipes of a layer and between layers, which 
is filled with cement mortar, while a 3-incli 
thickness of concrete mixed as above, sur- 
rounds the whole. A 36-inch mandrel which 
alignment in laying the duct and prevents 



O-'OO^^ 




DO 



201. Cross=section of Iron=Pipe Conduit. 




202. Clay Conduit in Cement 
Mandrel. 



exactly fits the bore, preserves ths; 

mortar getting inside. The bottom of each 18-inch length duct is slightly curved 

upward, so that the joints may not interfere with 

the drawing in of the cable. 

(4) The manhole (fig. 203), about 34 by 3^ by 7 
feet deep inside, for allowing cable lengths to be 
drawn into the iron or earthen duct and for con- 
necting su])ply branches, is built of brick and 
made water-tight. The masonry extends below 
the duct level to form a catch basin, and is pro- 
vided at top with a cast-iron ring frame support- 
ing two covers, the lower being screwed down 
upon a rubber gasket, and the other resting 
loosely on top. Both covers permit ventilation. 

(5) For means to draw in the cable, push through a duct a steel wire, or 4-foot 
wooden rods, jointed, from one manhole to the next. This serves to pull through 
a small rope, then a large rope, then a cleaning steel scraper and brush, and 
finally the cable. 

(6) Avoid twist and strain on the cable by 
the use of a swivel clevis attached to several 
iron wires wrai)ped spirally over the first 2 
feet. 

(7) Specimen underground cable (fig. 
206) to be (a) No. 14 single or larger con- 
ductor in strand of wires, uniformly sized, 
tinned and twisted ; (b) covered with one or 
more layers of pure Para rubber, tape spi- 
rally wound, half lapping; (c) then coated 

^ I two or more times with rubber compound, 
"^ — [- each coat of two tapes laid on longitudinally 
and pressed into half-cylinder forms which 
unite in good longitudinal joints ; (d) tightly 
bound with prepared rubber tape spirally 
wound. Then the rubber is vulcanized, the 
insulation is tested, and the outside taj^e and 
braid or lead is laid on. 

8. Overhead lines. — (1) Erected in forts 
only where fully protected from fire or for 
203. Manhole. temporary uses. 

(2) Never attached. to trees, buildings or outside concrete walls. 

(3) Wires. — Hard drawn copper. No. 14 and larger, of 60,000 pounds tensile 
strength, 00 per cent conductivity of pure copper and tinned, is coated with ,.\- 
inch thickness of vulcanized rubber and covered with one or more cotton or 
hemp braids saturated with moisture and fire repellant; bare aluminum, 58 per 




mm^imjm^.. 



SPECIFICATIONS FOR KE(^)UlSITIONS, ETC. 



153 



cent conductivity ; bare galvanized iron in uninhabited country for signal i)nr- 
poses only. 

(4) In contact only Avith double petticoat porcelain or gla.ss insulators and run 
at least 1 foot apart and in such manner that water can not cro.ss-connect. 

(5) Protected when necessary from accidental contacts with other lines by 
insulated, dead guard, iron wires. 

(6) Led into buildings through noncombustible insulating tubes slanting 
upward toward the inside. Drij) loops outside, .safety cut-outs inside. 

(7) Strain on wire for tying nut to exceed one-third its tensile strength. 




204, 205, 206. 

(8) Sag = 1 t(i 2 per cent of distance between poles, dei)endingon extremes of 
heat and cold. 

(9) Signal wires unavoidably paralleling heavy current lines are stretched 
along lowest cross-arms. See Line Construction, page 155. 

(1.0) A lightning-arrester in plain view is jilaced alongside of every overhead 
line near the point where it has entered the building, and is connected with a 
good ground (not gas pipe) by No. G copper wire direct as possible to ground. 
A choke coil is between arrester and dynamo. 

(11) Poles. — {(() Wrought-iron tubing; or wood of cedar, chestnut, pine, or 
spruce, round or octagonal, tapering to G inches at top and painted. Galva- 
nizing the iron or creosoting the wood may preserve the poles thirty-five years. 
They are 30 to 60 feet long, have one- 
fifth to one-tenth of their length in the 
ground, according to soil, pole lengtli, 
and inimber of wires, and stand verti- 
cally in as .straight a line as possible, 
1 '"■■■) feet apart. Lengths may vary with 





the cfintour to keep the line more nearly straight. At unavoidable curves 
heavier ])oles are inclined outward, guyed or double-guyed laterally on the 
outside by strands of No. 6 or S galvanized iron from beneath the single cross- 
arm, or the middle of the lower half of several cross-arms to a guy stub or 
anchor, or they are braced on the inside by a half pole, solidly planted and 
bolted at 30 angle witli the pole. 

In raising, two .spikes may replace the ladder; the "dead man " holds what- 
ever is gained in raising. 

(b) Cross-arms of iron are clanqx-d; of clear yellow i)ine or oak wood are 
bolted (fig. 208) into gains cut in the poles, braced with iron and spaced as showni. 
The pins are of locust. 




154 HANDBOOK FOR ELECTRICIANS. 

(c) Guys of iron strand are put laterally on every tenth pole of a 
straight line, on all poles from which service wires lead to either side, 
and longitudinally on the two poles of an unusually long span and 
the two or three end poles of every line. 

(13) Insulators of porcelain or blown glass, subject to not less than 
a 6,000-volt, 5-ainpere, break-down test, have the two or three petti- 
coat form, and are screwed to iron or oak" pins which are bolted or 209 
screwed to the cross-arm. 

(J) ITEMS NOT PREVIOUSI.Y SPECIFIED, 

(Brackets refer to manufacturer.) 

Annunciator, index or gravity drop. 

Anti-hum, Clarke. 

Arc lamp, inclosed [G. E.]. 

Babbitt metal, "Best." 

Bases, porcelain of all kinds [G. E.]. 

Bell, single stroke, "Vigilant" or "Covered." 

Bell, vibrating, dust and water tight [W. E. ] . 

Binding post, English [W. E.] or Nos. 1, 2, and connectors [Mn. ]. 

Boards (panel), marine type [W. E.]. 

Boxes (junction, outlet, switch), iron-armored or marine [W.E.]. 

Buzzer, Eco or Lungen. 

Call box, Firman with Ans. back [B. ]. 

Clamp, Klein or "parallel." 

Conduit, iron -armored insulating [W. E.]. 

Connectors, Mclntire. 

Cut-oiits, bases, receptacles [G. E.]. 

Drill, hand, hollow handle [W. E.]. 

Gong, clock to 60 strokes, marine [W. E.]. 

Gauge, calculating U. S. Wireman's [Mn. ]. 

Gauge, caliper, Micr. 0.001 to 0.5 inch [Mn.]. 

Instruments, portable, Weston. 

Insulators, glass, 2 or 3 petticoat. 

Insulators, porcelain, F. H. screw or G. E. knob. 

Junction box, iron-armored or marine. 

Lamps, incandescent, Navy [G. E.]. 

Pliers, Stubs or "Universal" [Mn.]. 

Push button, plain, bronze, water-tight. 

Receptacle, water-tight [G. E.]. 

Rheostat, Carpenter. 

Socket, lamp, marine [G. E.]. 

Soldering torch, gasoline, Imperial or Wellington. 

Soldering furnace, "Combination" or " Universal." 

Speed indicator, Starrett. 

Switch (in closet or on switch board), knife [G. E., W. E., or Mn.]. 

Switch (in conduit) snap, D. P., marine. 

Switchboard (dynamo or battery) [G. E., W. E. or E. S. B.]. 

Switchboard, telegraph or telephone [W. E.]. 

Telegraph instruments [Bunnell] : 

Key, steel lever, solid trunnion, with or without legs. 

Key, cable, on rubber base. 

Relay, Western Union. 

Relay, box and key combined. 

Relay, pocket, nickle-plated [W. E.]. 

Relay, polarized, armature lever vertical. 

Register, ink, self stai'ting and stopping, one or more pens. 

Set, polar duplex, W. U 

Set, quadruplex, W. U. 

Testing set, magneto to ring through 50,000 ohms. 

Tool handle, "Cocobolo." 

Tool handle, eleven tools [W. E.]. 

Voltmeter, recording, Bristol's. 

Wheatstone bridge [W. E. or Biddle]. 



SPECIFICATIONS FOR REQUISITIONS, ETC. 155 

(K) RULES GOVERNING EINE CONSTRUCTION. 

9. (1) Small conductor resistance, large insulation resistance, order, perma- 
nency and accessibility characterize good wiring. To wire neatly and effec- 
tively is an art. 

('2) Wires which are separately insulated run at least 1 inch apart, parallel if 
in the same direction, straight between the fewest possible insiilators, in contact 
with insulators only, and in such a way that no two wires can ever touch each 
other. 

(:5) Avoid temporary work : in construction regard all other wires as "live" 
and bare. 

(4) If a kink or a nick occurs in the conductor, cut it out. If the insulation 
gets damaged, paint and tai)e the conduc-tor as in .iointing. 

(5) In cutting a wire, grip it with the cutting jaws of the pliers so moved as 
to cut an arc of a circle. Twisting breaks the knife edge. Then grip the wire 
with the flat jaws close to the cut and one or two sharp twists will give a sciuare 
break. 

(0) Avoid "come alongs" or vises when they tear the insulation, but take a 
series of half liitches or noo.se wrap with a small rope. 

(7) Jointing electrical conductors is of hourly occurrence and requires the 
care and skill acquired only by practice. 



ZiO, 211. 

(a) Joints in copper or aluminum lines are often made with the Mclntire 
(fig. 210) connector. The two ends brightened are slipped from the opposite 
directions into the close-fitting double sleeve which is then twisted l)y special 
pliers. Solder the ends (mly to avoid annealing the main line and smooth down 
projecting parts which might pierce the insulation. 

{}>) The lineman's .splice (fig. 212) for galvanized iron, sometimes for soft cop- 
per, is made by holding the two cleaned ends at an 
angle in a hand vise, and twi.sting with pliers by half dl 
turns each end in succcession five times closely around , 

the line and soldering. 

((•) All joints of insulated wire, after being cleaned and thoroughly dried, are, 
as a rule, alternately painted with a thin, uniform coat of rubber or other solu- 
tion, and wound with tape half la])ping. Each winding is a little longer than 
the one before it and runs oppo.sitely. In stripinng insulation to make a joint, 
cut as in whittling toward the ends into a lead-pencil shape. For special wires 
follow the manufacturer's directions in jointing. 

(il) The ends of a strand are separately joined by a twist or a connector, as 
above, in places not opposite, to avoid too large a bunch when finished. Then 
paint and tape alternately. 

((') The ends of a large solid core are beveled and notched for at lea.sf 1 inch, 
then .soldered together into a round piece of the .same diameter as the conductor, 
then wrapped closely with fine copper which is also solidly soldered, ami the 
whole is finally taped. Tlie finished insulated joint is considerably larger in 
diameter than the cable. 

(/) ln.sitl(iti)i(i joints — Carefully cut the ends of the insulation, and clean 
with a little benzole. Rub a little rubber solution over, and then carefully 
wind sjurally over the joint and ta]tered end of the insulation, pure rublter tape, 
(.'over this with rul)ber .solution and wind on more until the diameter of joint 
is about the same as the re.st of insulation. Over this and for alxnit two inches 
on each side of the cut ends of the insulation, wind especially prepared braid- 
ing. Finally varnish the whole. 

(r/) ]'itlc(i»iz('il rnbhcr j(>i)its. — Cover joint with pure rubber strip. Rub in 
some special rubber solution, allow to dry, bind with valcanizing rubber tape 
three or four layers. Then with prepared rubber tape cover the whole witli a 



156 HANDBOOK FOR ELECTRICIANS. 

piece of strong silicia cut to length of joint and then rolled round it, having a 
longitudinal seam. Bind this with strong cotton selvedge tape. Joint is now 
ready for the cure, which consists in subjecting it for half an hour or more to 
the action of molten sulphur, the joint being placed in a specially made box for 
the purpose. Molten sulphur is run out, and joint cooled, the outer wrapping 
of silicia and cotton removed and, if the vulcanizing is satisfactory, the joint is 
finished by braiding and varnishing. 

(h) Most large cables and special makes have specially designed mechanical 
joint boxes. 

(i) Make as few joints as possible. Solder all joints or other surfaces perma- 
nently in contact. 

ij) Solder is to prevent rust between the wires of a joint; acid for cleaning, or 
a flux will later cause rust. Therefore use resin. 
Use the soldering iron for small 
wires and dip the large wires in 
molten solder or pour on with 
a ladle. In all cases avoid burn- 
ing the insulation. 

{k) Work with clean hands in 
213- ^ insulating a joint. If the tape ^*"*' 

gets burned or dampened or dirtied, cut the piece out and begin again. 

(8) A standard tie is made by a short length of tie wire, bare or insulated like 
ths main, but one or two numbers smaller. Fig. 213 is for galvanized iron ; fig. 
214 is for H. D. copper main, which should not be bent. 

(9) A lightning rod of No. 6 bare galvanized wire extends from 1 foot above 
the top of every tenth i)ole to a few hand turns of the wire buried at its foot. 





INOBX. 



Batteries, Primary 114 

AnialfraniiitiiiK zincs 114 

BichninmU' 117 

Care of 114 

fc'lls, lii>\v joini-d 11 '> 

Cop|M-r ..xiili- lir, 

Cuni-iit Wfakeiis 114 

Dirfctions, (reiienil 114-5 

Disniuunting lir>-7 

Dry 1 \r, 

Eagle lit: 

Gravity , ll.'> 

FuIUt 117 

Kiiidsnf lir. 

Li-(';aiirli.' ll."> 

Local action 114-7 

MaiNtfiiaiK'c 115-i>-7 

Maiia;;ciii('llt 114 

Aluiiiitiiii; 115-0-7 

Poliiri/Htion 114 

Principles 114 

Qualities of good 11.") 

Kooni 114 

Bon. Kits. Steam 7 

Bunking flri'3 8 

Blow-off 10 

Caio of 8 

Cleaning i;j 

Cleaning tires 8-!) 

Corrosion \:i 

Explosion:* . 14 

Feeil water 115 

Firing 7 

Fittings 

Foaming . S 

Gauge gla.ss -ji 1(1-17 

Incrustation IH 

Injector 12 

Inspection \:\ 

Low water 8 

Lying iille 9 

Mnnagenieiit of 8 

Material 9 

Piping 9,47 

Plug, fiisihie Itl 

Pressure gauge 10-13 

Priming 8 

Pump 10 

Safety valve 9 

Steam gauge 8 

TiKils _ 7 

Dynamos, D. C 49 

Armature 43-4-6, 51-2 

Bare 1 ._ 45 

Bearings 45, .VJ 

Brush holder 49, .10 

(15: 



Page. 

Dynamos, D. C. — Continued. 

Brush setting 5ii-.'i 

Care of F>:i-5 

Coils, armature 44 

Commutator 42-5, 50-3 

CompiiMMiling 49 

(\<i\\ armature 44 

Diseases 52 

Drum 43-4 

Failure to generate 53 

Kii-lil, magnetic 42 

Fii-lil, winilings 45 

Founilatioiis 47 

Fuse tiring 4<1 

O. E., D. C. sets. 47 

Generates ulteioiating C 42 

Governor . 48 

Heating 52-5 

Induction, laws of 42 

In parallel 51-4 

Inspection 53 

Maiiageineiit of .'iS- 

Lap winding 43-4-5 

Lead 55 

Noise 52 

Oil rings 45 

Packing 49 

Piping 47 

Pressure 47 

Ring winding 43-4 

Ituiining ... 47, .54 

Self-exciting 43 

Special service 4(i 

Speed 47-8, .53 

Spools , 49 

Starting 51-4 

Steam pipes 47 

Stopping 55 

Telephone call 4li 

Tested 47, 51-2 

Troubles 52 

Valves, relief 48 

Wave winding 4;i— 4 

Wi'slinghouse (fig. 74) 72 

Windings 45 

Enc.ink, Oil, II.-A 29 

Air inlet 34-« 

.Mtenitions, fundamental 39 

Crank positions 35 

Critical positions 29 

Cycles 29 

Cylinder 29,38 

Exhaust 34-8 

Failure of 'id 

Fly wheil 3t5 

Governor 27, 37 



158 



INDEX. 



Page. 

Engine, Oil, H.-A. — Continiicil. 

Goveruor bracket 36 

Ignitiou retarded 38,41 

Indicator cards 29,41 

Instructions for 35 

Lamp, heating 35 

Oiling 3G-9 

Oil tank 38 

Nomenclature 31 

Piston 35-8 

Piston's strokes 29 

Port 35 

Principles of 29,31 

Pump 34-6 

Kegulation . 34-7-8 

Running 37 

Skew wheel 39 

Spray hole 38 

Starting 35-6 

Starting gear 36 

Stopping 39 

Strokes 29 

Testing 40 

Valve box 34-7-8 

Valve, horizontal 34-8 

Valve, vertical 34 

Vaporizer 29,35-6-8 

Water supply." 38 

Works well 39 

Engine, Steam 16 

Adjustments 17-23 

Angle of advance 18,20-22 

Bearings 25 

Care of 17 

Clearance 25 

Connecting rod 25 

Crank 17 

Cross-bead 25 

Cut-off 19,22 

Dead center 23 

Eccentric arm 20-2 

Exhaust 17 

Full port 18 

Governor 22-7-8,48 

Heating 17-8 

Inspection 23 

Knocking 17 

Laps 18 

Lead 18 

Level 23 

Lining up 23 

Lubricator 18 

Management of 17 

Oil 17 

Operation 16 

Packing 17,25,49 

Piston, fit of 23 

Piston strokes 17,21 

Piston valve 27 

Pressure 47 

Positions, critical 20 

Running 16, 51 

Slide valve 25 

Speed 47-8 

Starting 16,51 

Stopping 16 

Strokes, piston 17, 21 



Page. 
Engine, Steam— Continued. 

Testing 23, 47 

Travel, piston's 18 

Valve's positions 18,20 

Valves, relief 48 

-> Valve slide 25 

Hoist Ammunition 88 

Automatic safety stop 88 

Connections 89 

iNSTRUCTION.S, SPECIAL 5 

Directions, printed 5 

Text books 6 

Measurements and Tests 141 

Apparatus required 141-2^ 

Armature resistance 142 

Battery resistance 144 

Cable's insulation 144 

Care of instruments 141 

Conduction resistance 141-2 

Connections 143 

Continuity of circuit 141 

Current strength 141 

Crosses 144 

Difference of potential 141 

Dynamos 144 

Electromotive force 141 

Galvanometer resistance 144 

Grounds 143-4 

Insulation resistance 142-3-4 

Joints 142-3 

Magneto 144 

Open circuit 143 

Resistance, battery 144 

Resistance, conduction 141-2 

Resistance, insulation 142-3-4 

Resistance, small 142-3 

Resistance, ordinary 141-2-3 

Storage battery, resistance 144 

Telephone, use of 144 

Wheatstone bridge 141-2 

Laws, Examples, Tables 135 

Bridge wire, table 137 

Capacity 135 

Cells, combined 136 

Copper wires, table 137 

Current, strength 135 

Difference of potential 135 

Direction of current 135 

Divided circuit 136 

Electromotive force 135-6 

Equivalents 135 

Examples 138-140 

Feeder, sizes 139 

Formula, general 138 

Fuses, sizes 138 

Gauge, wire 137 

Heat 135-6 

Kilowatt 135 

Metal deposited 137 

Ohm's law 135-8 

Power 135-7 

Quantity ,_ 135 

Resistance 135-6 

Safety fuses 137 

Sizes of wires 138-9,140 

Table, wiring 137 

Taps 138-9 



INDEX. 



159 



PiiK.-. 
Laws, Kxamples, Tables — Continued. 

I'liderwriterB' table 137 

I'nits i:*.') 

Wires, copper 137 

Wire, size of 137-8-0 

JIlSCEI.I.ANF.Ol'8 109 

Anemometer 112 

Battery, tiring ,.. „ 110 

Bells, electric 111 

Cure of iinemometer 113 

Connections 110 

Detonator 111 

Dynamo, firing 110 

Failure to fire IIO 

Firing battery 1U( 

Firing key 1(K) 

Fuses 10!i, 110 

Ilecbauism 111-2-3 

Mine charge 110 

Mine fuse 110 

Placing the fuse 110 

Precautions in firing HI 

Pressure, wind 113 

Self-register 112 

Stop-clock 112 

Velocities of wind 113 

Wiring, . 111 

Motors, Electric, D. C 7,>' 

Adjusting rheostat 81-3 

Back E. M. F.. 78 

Blow-out (figs. 107-8,110).. 82-3 

Booster 87 

Care of. 84 

Compound 80 

Connections 80-3-6 

Controller 88 

Cores 79 

Direction of rotation 78 

Dynamotor 80 

Electric hoist 88 

Efficiency of 78 

Heating 85 

Hoist, electric. 88 

Installing 83 

Leoniint 8.5 

Management of 84 

Motor generator 86-7 

Multipolar (fig. 118) 78-9 

Overload, C. B 83 

Principles 78 

Protection to 80 

Regulation 80 

Keversing 86 

Rheostat, S. and S. (figs. 109, 110) 80-1 

Kheostats, installing 83 

Running 84 

Shunt 79, 82-3 

Series 79, 81-6 

Special forms S5 

Special uses 79 

Starting jl. 84-5 

Starting box 80 

Stopping 86 

Switch 83 

Teazer system 8t> 

Inderload, C. B 83 

Watt-hour meter 85 



I'age. 

JIciTous, Electric, D. C. — Continued. 

Westinghouse (fig. 118) 87 

Winding 79 

NluiiT-SiiiNAL Sets 103 

Assembling lori 

Bougliton set UNi 

Cable 103-.6-»! 

Connections lOS-.'i-e 

Contndler, trucklight. 107 

Keyboard (fig. 137) 103-^> 

Ladder 104 

Lanterns 104 

Mechanism 103 

(•peration 104-s 

Packings 106 

Plug :.. 104-6 

Receptacle _ 104-6 

Switch, controlling 107 

Truck light 106 

I'. S. form UK) 

Wiring 103-5-6 

Searcm-Lioht Projectors 90 

Arc 98 

Automatic feed 96 

Base sheeting 97 

Beam 91-2 

Cable 98,101 

Carbons— 90,91-4-6 

Carbon holders 93 

Carlioning lamp 93-6 

Care of lamp 94-5-6,101 

Connections 97-8-9,100 

Controlled 91 

Controller (fig. 123) 97-8 

Couplings 102 

Covei-8 - 102 

Crater _ 95 

Current 91 

Dead resistance 99 

Diagrams 1.. 130-1-2 

Drum 91 

Feeding 91-6 

Field (figs. 136-6) 102 

Flaming 96 

Front door 92 

Focusing lamp 94 

General Electric Co. "s 90 

Hand control (fig. 133) 90 

Hissing 06 

Illumination 102 

linage of aiv 94 

Installing 92-7-9 

Ijinip mechanism (figs. 124-7-8) 93 

Largest size 102 

Ijocation 102 

Mechanism (fig. 124) 9,5-7-8-9 

Methods of observing 102 

Minor _ 101 

Motors 97-8 

Mushroom 96 

Names of parte ' 92-3-7 

Navy 90 

Observers 102 

Operating .' 101 

Operating lamp 93-4-5-6 

Operators 102 

Parabolic mirror 90-2 



160 



INDEX. 



Page. 
Search-Light Projectors — Continued. 

Pilot-house 91 

Placing lamp 93 

Probability of injury 102 

Rheostat 90 

Schukert (tig. 120) ■ 90 

Screen shutters 91 

Signaling with 102 

Small motion 101 

Speed of control 92 

Sizes 90 

Starting magnet 94 

Striking the arc 90 

Switch controller 98 

Training mechanism 98 

Transportable 102 

Truck 92 

IT. S. form (fig. 123) 92 

Voltage 95-6,101 

Wiring 94-6-8-9, 100 

Specifications 145 

Armatures 147,43-4^6,51 

Battery room - 145,65 

Blow-off - 146, 16 

Boilers 145,7 

Cabinets 150 

Cables 152 

Circuit breakers 149, 150 

Closet system 149 

Conduit 151-2 

Construction of lines 154 

Cross-arms 153 

Cro-shcad . 145, 25 

Cut-outs 149, 57-8 

Deadman 153 

Duct 152 

Dynamo 146-7, 47 

Dynamo room ^ 145,48 

Engine 146-7, 16 

Feeders 149 

Filament lamp 148 

Fuses J 149, 109 

General rule in specifications 145 

Generators 146-7, 47 

Governor engine 147, 2-7-8 

Guides 146, 23^ 

Guys . 154 

Injector, steam 146, 12 

Insulating joints 155 

Insulators 154 

Items, miscellaneous 154 

Joints 155 

Lamps 148 

Lightning-arrester 153 

Lightning rods 156 

Lubricator 147, 18 

Mandrel 152 

Miscellaneous items 154 

Motors 148, 78 

Outlets 151 

Overhead lines 152 

Piping 146, 152, 9 

Piston rod 146 

Poles 153 

Power house 145 

Projectors 148, 90 

Pump 146 



Page. 

Specifications — Continued. 

Rheostat, motor 148 

Safety valve 146, 9 

Searchlights 148, 90 

Shaft 146 

^ Sockets, lamp 149 

Solder 156 

Steam gauge 146, 8 

Storage batt'ery 147, 65 

Switchboard 147, 56 

Switches 150-1, 57, 61 

Ties 156 

Underground lines 151-2 

Vulcanizing rubber 155 

Wires 150-1-2 

Wiring . 149,151-2-3 

Storage B.ittery 65 

Back, E. M.F 68 

Battery room 65 

Buckling 76 

■ Booster connection 75 

Care of 67 

Charge of 07 

Charging, initial 67,76 

Connecting up 66,74-5-7 

Current 67 

Density of solution 67-9 

Discharge 69 

Drop in voltage 69 

Electrolyte 66-8-9, 71-2 

End cells 62^1-8 

Endurance 76 

First charge 66 

Gassing 68, 71 

Good condition 66 

Inspections 70-1 

Insti-uctions 67 

Instruments 69, 74-5 

Jars 65 

Maintenance 70 

Management of 67,70 

Maximum rate 67 

Mixing solution 70 

Object of 65,76 

Out of commission 72 

Polarity 77 

Portable 76 

Eeoords 71-2-3 

Kestoration 68 

Eoom 65 

Sediment ; 70-1 

Separators 66 

Setting up 65 

Shipment 66 

Specific gravity ^ 67-8-9 

Stand 65 

Sulphating 76 

Switchboards 74-5 

Temperature effects 67 

Unpacking 65 

Voltage 67-S-9 

Switchboards " 56 

Ammeter 56, 60 

Apparatus 56, 60 

Arrangement 56 

Back connections 61 

Best for forts 56 



INDEX. 



161 



Page 

Switchboards — Continued. 

Care of »>4 

Circuit breakers 57-S 

Conditions fulfilled 56 

Connectiung 66 

Design 56 

End cells 62-4-8 

Engineer 57-8-9 

Fuses 61 

Golden Gate board 63 

Key West board 62 

Location 66 

Management of 04 

Overload, C. B bl-H 

Operation uf 64 

Panel 56 

Preble l)oard 62 

Switches 57,61 

rnderU>a<!, C. B. 67-8 

Voltmeter 56-7 

Telegraphy UK 

Abbreviations 119, 121 

Adjustments 119,120 

Bcgiunerj 12(^-1 

Breaks 122 

Care of 12(M-^)-7 

Code 118-9, 121 

Code, artillery 122 

Code, calls 121 

Code, signal 121 

Dash ... UK 

Diagrams 118,120-1 

Directions 120 

Dot 118 

Escapes 123 

Faults, line. _. 123 

Fog, siiriials 122 

Heliogniph ._ 122 

Installing 126 

Instructions 120-1 

Key... -.* 118, 120 

Lantern 121 

Lineman 123 

Management 124-«) 

Message forms 119 

Morse 118 

Operation 124 

Principles tclautogniph 123 



Page. 

Telegraphy— Continued. 

Receiving 120-1-2 

Relay 118, 120 

Searchlight 121-2 

Sending 120-2 

Setting up heliograph 122 

Signal flags 121 

Sounder , lis 

Space, signal UK 

Sticking 120 

Telautograph _ 12:1 

Torch 121 

Transmitter (fig. 167) 123-6 

Wigwag 121 

Telephony l2^ 

Adjustments 131 

• .\pparatus 12S 

Battery 131 

Bell, polarized... 128, 13(V1 

Bridge 12K 

Care of 130-1 

Central station 133 

Common battery 132 

Connections 128-8 

Cross-talk 131 

Details 128 

Drops 133-4 

Dynamo 41; 

Faults 1.30-1 

Handling 1,30 

Holtzer Cabot 132 

Induction 131 

Intercommunicating 131 

Jacks 134 

Keys 133 

Ma'gneto 46,128,131 

Management .„ 130 

Nunilieron circuit . 130 

Noises, induction 131 

Parallel connections 131 

Receivers 12S, 131 

Secon<lary coil 128 

Series connections 128 

Transmitter 128, 131 

Troubles 1,30 

I'sing 1.30 

Without central .» 132 



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